Novel pharmacological chaperone compounds of human acid alpha-glucosidase and the therapeutic use thereof

ABSTRACT

The invention concerns particular compounds of the iminosugars class, with a piperidine ring, having a D-gluco configuration and comprising a quaternary centre in the a position of the nitrogen of the piperidine ring. These compounds have the ability to stabilize human acid α-glucosidase while being selective with respect to other glycosidases. They are particularly advantageous for use as chaperone molecules of this enzyme for the treatment of Pompe disease.

CROSS-REFERENCE TO RELATED APPICATIONS

This application is the U.S. national phase of International ApplicationNo. PCT/EP2021/060572 filed Apr. 22, 2021, which designated the U.S. andclaims priority to FR Patent Application No. 2004065 filed Apr. 23,2020, the entire contents of each of which are hereby incorporated byreference.

BACKGROUND OF THE INVENTION Field of the Invention

The present invention lies in the field of the treatment of lysosomaldiseases, more specifically the treatment of Pompe disease.

More particularly, the present invention relates to compounds, belongingto the class of iminosugars, capable of selectively interacting withhuman α-glucosidases and in particular of stabilizing human acidα-glucosidase in its endogenous form (GAA) or of recombinant nature(rhGAA), in a conformation favoring transport thereof to the lysosome,for use thereof as a drug, in particular for treating Pompe disease; andto a pharmaceutical composition containing such compounds. The inventionalso relates to compounds belonging to the class of iminosugars capableof selectively interacting with human acid α-glucosidase. The inventionfurthermore relates to a method for preparing such compounds.

Description of the Related Art

Pompe disease, or type 2 glycogenosis, is a rare genetic diseasecharacterized by one or more mutations of the GAA gene encoding thehuman acid α-glucosidase (GAA) lysosomal enzyme, which causes a deficitin the activity of this enzyme, and consequently the accumulation ofglycogen, the hydrolytic biodegradation of which is performed by thisenzyme, in the lysosomes, which causes cell malfunctionings in themuscles and heart. The symptoms are diverse, and progression thereofmore or less rapid depending on whether the disease manifests at birthor at an adult age. They affect all the muscles, in particular therespiratory muscles and the myocardium. The life expectation of thesubjects affected is reduced thereby, especially in babies, who die inthe course of their first year of life.

At the present time there is only one treatment for Pompe disease thathas received authorization for marketing. This treatment, known asenzyme replacement therapy (ERT), consists in intravenouslyadministering the Myozyme® specialty, the active principle of which is arecombinant human acid α-glucosidase (rhGAA), which makes it possible tostabilize the symptoms of the disease. However, this treatment hasnumerous drawbacks: it is very expensive, binding for the patient, sinceit requires perfusion every two weeks, in a hospital environment, and itis of limited efficiency in many cases. It may indeed cause an immunereaction affecting its efficiency and its tolerance by the subject beingtreated. Furthermore, the recombinant enzyme is relatively unstable inthe blood, and the doses that have to be administered to the patientsare much greater than those administered for treating other lysosomaldiseases.

There thus remains at the present time a need for a satisfactorytreatment of Pompe disease.

SUMMARY OF THE INVENTION

The present invention aims to propose such a treatment. Moreparticularly, the invention aims to propose compounds affordingeffective treatment of Pompe disease, this treatment furthermore beingeasy to administer, and less expensive than the treatment by enzymereplacement therapy proposed by the prior art. An additional objectiveof the invention is that these compounds, administered at the same timeas the enzyme replacement therapy treatment of the prior art,significantly increase the efficiency of the latter.

Seeking to achieve these objectives, the present inventors becameinterested in a therapeutic approach considered at the present time tobe one of the most promising for treating lysosomal diseases: the use ofso-called pharmacological chaperone molecules. Chaperone molecules aresmall molecules promoting the correct folding of mutant enzymes andenabling transport thereof to the lysosomes (Boyd et al., 2013, J. Med.Chem. 56: 2705-2725) rather than degradation at the endoplasmicreticulum. This therapeutic approach was implemented successfully foranother lysosomal disease, Fabry disease, against which the migalastatiminosugar (Galafold®) is now prescribed as a pharmacological chaperoneof acid α-galactosidase (Markham, 2016, Drugs 76: 1147-1152).

The present inventors have thus sought compounds capable of stabilizinghuman acid α-glucosidase in its active folded form, as well asincreasing the efficacy of the recombinant human acid α-glucosidase usedin treatments by enzyme replacement therapy, in order to use them in thetreatment of Pompe disease.

Among the existing compounds, deoxynojirimycin (DNJ), an iminosugar offormula:

has been proposed by the prior art as potential chaperone molecule ofhuman acid α-glucosidase (Flanagan et al., 2009, Hum. Mutat. 30:1683-1692).

A derivative of DNJ, called NB-DNJ, of formula:

has also been proposed by the prior art for the same application(Parenti et al., 2007, Mol. Ther. 15(3): 508-14).

However, these compounds have low selectivity for this enzyme, and theyinhibit other human enzymes, both of α- and β-glycosidase type, andglycosyltransferases, which causes many undesirable side effects whenthey are administered to a subject.

The publication by Boisson et al., Org. Lett., 2015, 17(15), 3662-5describes particular polyhydroxylated derivatives of indolizidineshaving good ability to inhibit an α-glucosidase of S. cerevisiae and arice α-glucosidase.

The publication by Tangara et al., Org. Lett., 2017, 19(18), 4842-5,describes particular aziridinyl-iminosugars.

The publication by Vieira Da Cruz et al., J. Org. Chem., 2017, 82(18),9866-72 describes particular polyhydroxylated quinolizidines and theirability to inhibit yeast and rice α-glucosidases.

The present inventors have now discovered that specific compounds,belonging to the iminosugars class, complying with a particularstructure derived from that of DNJ, bind to human acid α-glucosidase(GAA) and stabilize it, and this in a highly selective manner, i.e.without interacting, at least significantly, with other humanglycosidases, in particular with human β-glucocerebrosidases (GBA1 andGBA2), human β-glucosylceramide transferase (GCS) or with the humanendoplasmic reticulum α-glucosidase II (GANAB). The effect ofstabilizing GAA by these compounds is furthermore particularly great.Thus, administered to patients suffering from Pompe disease, thesecompounds make it possible to stabilize their endogenous acidα-glucosidase in a correctly folded form to improve transport thereof tothe lysosomes and to increase its activity of hydrolysis of glycogen,and therefore to effectively treat this disease, while reducingundesirable side effects during treatment. These compounds also make itpossible, associated with enzyme replacement therapy (ERT), to stabilizethe recombinant enzyme (rhGAA), thereby increasing the efficacy thereof.

Molecules with a similar, but different, structure, such as DNJ orNB-DNJ, do not make it possible to obtain such a particularlyadvantageous result on a therapeutic level.

Thus, according to a first aspect, the present invention relates to acompound of general formula (I) below, or one of the pharmaceuticallyacceptable salts thereof, for use as a drug, in particular as apharmacological chaperone, in particular for treating Pompe disease, inparticular for stabilizing human acid α-glucosidase:

wherein:

-   -   R¹ represents a hydrogen atom or a linear, branched and/or        cyclic hydrocarbon radical, saturated or unsaturated, aromatic        or not, optionally substituted, optionally comprising one or        more heteroatoms and/or one or more groups including at least        one heteroatom and optionally comprising a single ring or a        plurality of rings optionally fused,

and R² represents a linear, branched and/or cyclic hydrocarbon radical,saturated or unsaturated, aromatic or not, optionally substituted,optionally comprising one or more heteroatoms and/or one or more groupsincluding at least one heteroatom and optionally comprising a singlering or a plurality of rings optionally fused, said hydrocarbon radicalcomprising at least 2 carbon atoms when R¹ represents a hydrogen atom,

-   -   or R¹ and R² form together, with the atoms of the piperidine        ring to which each is attached, a 3- to 6-membered heterocycle        fused with the piperidine ring, optionally substituted by one or        more radicals, which may be identical or different, each        selected from a hydroxyl group, an amino group or a carbon        radical, preferably comprising from 1 to 18, preferentially from        1 to 12 and in particular from 1 to 6, carbon atoms, linear,        branched and/or cyclic, saturated or unsaturated, aromatic or        not, optionally substituted, optionally comprising one or more        heteroatoms and/or one or more groups including at least one        heteroatom and optionally comprising a single ring or a        plurality of rings optionally fused. Such a configuration        encompasses the cases wherein the carbon radical is branched to        the 3- to 6-membered heterocycle by a carbon atom, as well as        the cases wherein the carbon radical is branched thereto by        means of a heteroatom that it includes.

The term heteroatom designates, in the present description,conventionally per se, any atom belonging to an element other thancarbon and hydrogen, such as a nitrogen, oxygen, sulfur, phosphorus,silicon, halogen, etc. atom.

Preferentially, when R¹ represents a hydrogen atom, R² does notrepresent a methyl radical or a benzyl group.

In the present description, “pharmaceutically acceptable salt”,conventionally per se, means any salt of the compound of general formula(I) comprising, as a counter-ion, a substance that does not produce anyadverse, allergic or otherwise undesirable reaction when it isadministered to a subject, in particular to a mammal.

Any conventional pharmaceutically acceptable salt of the compound ofgeneral formula (I) can be used according to the invention. By way ofexamples, mention can be made of chlorides, bromides, formiates,acetates, etc.

In the present description, the term “treatment” means the obtaining ofa desired pharmacological or physiological effect. The word “treatment”,as used in the present description, comprises the prevention or thepartial prevention of one or more of the symptoms of the disease and/orthe partial or total curing of the disease and/or the total or partialdisappearance of one or more of the symptoms thereof.

Human acid α-glucosidase is a protein of 952 amino acids, of GenBankAccession No. AB153718.1.

The compound used according to the invention, having the general formula(I), is a ligand thereof. It furthermore has particularly strongselectivity with respect to this enzyme. This selectivity is inparticular much greater than that of DNJ or NB-DNJ, or other iminosugarsinteracting with glycosidases.

The characteristics of the compound used according to the invention,relating in particular to the three-dimensional structure thereof, whichmake it possible to obtain such advantageous properties, will not beprejudged here. It can however be supposed that the followingparticipate therein: the presence of a quaternary center in the aposition with respect to the nitrogen of the piperidine nucleus, theD-gluco configuration of the compound, and the particular substituentspresent on the quaternary carbon in the a position with respect to thenitrogen of the piperidine nucleus and on this nitrogen. Because, atleast partly, of these characteristics, the compounds used according tothe invention would bind non-covalently with the enzyme and wouldstabilize the folding thereof, conferring on it a role of chaperonemaking it possible to restore the transport and the activity of thedeficient enzyme in the lysosomes.

The compound used according to the invention thus stabilizes the humanacid α-glucosidase at low concentrations, and it has the essentialproperties of pharmacological chaperones suitable for treating Pompedisease. In particular, at a concentration of 100 μM, it increases, invitro, the thermal denaturing temperature of the human acidα-glucosidase from 8 to 12° C. at pH 4.0 and the thermal denaturingtemperature of the human acid α-glucosidase from 10 to 13° C. at pH 7.4.The chaperone effect of the compound used according to the invention onhuman acid α-glucosidase is confirmed by experiments on human cells inculture, more precisely fibroblasts of patients suffering from thedisease, as well as, in vivo, in mice.

The compound used according to the invention is therefore entirelyadapted and advantageous for being used as a pharmacological chaperonefor treating Pompe disease, by selective bonding to the human acidα-glucosidase and stabilization thereof, thus restoring the activity ofthe deficient enzyme of the patient, and/or improving thebioavailability of the rhGAA recombinant enzyme administered duringrhGAA enzyme replacement therapy when this therapy is associated withuse of the compound used according to the invention.

Thus the compound of general formula (I) can be used for stabilizinghuman acid α-glucosidase in its active folded form, as well asincreasing the efficacy of the recombinant human acid α-glucosidase usedin enzyme replacement therapy treatments, the compound of generalformula (I) and the recombinant human acid α-glucosidase beingco-administered to the patient.

The compound used according to the invention can advantageously beadministered to the patient easily, in particular orally, and it isinexpensive to prepare.

It has a low risk of toxicity, and good bioavailability.

Furthermore, in association with enzyme replacement therapy, thecompound used according to the invention advantageously improves thebioavailability of the recombinant enzyme injected, which makes itpossible to reduce the doses thereof to obtain a same efficacy intreatment, and even superior efficacy.

The compound used according to the invention, of general formula (I),can be administered to any subject in need thereof, i.e. suffering fromor likely to contract the disease. This subject may in particular be amammal, and especially a human.

The compound used according to the invention is preferably administeredto the subject in a therapeutically effective amount.

“Therapeutically effective amount” means an amount of the compoundwhich, when it is administered to a subject to treat the disease, issufficient to ensure such treatment of the disease.

The therapeutically effective amount of the compound used according tothe invention depends on several factors, such as the disease and itsseriousness, the age, the weight, etc. of the subject to be treated, theparticular compound used, the route and form of administration, etc. Thetherapeutically effective amount of the compound used according to theinvention will be determined by the doctor for each individual case.

The compound used according to the invention can be administered to thesubject to be treated by any method conventional per se, in particularparenterally, for example subcutaneously, subdurally, intravenously, byintramuscular, intrathecal, intraperitoneal, intracerebral,intra-arterial or intralesion route; intranasally; rectally; bypulmonary route, for example by aerosol or inhalation, or eventopically. It is preferentially administered orally. Determining theadministration posology of the compound used according to the inventionfalls within the competence of a doctor. The compound can for example beadministered to the subject in need thereof once or twice per day, overa long period, at regular intervals, or in a targeted manner during anassociated treatment by enzyme replacement therapy.

As disclosed above, the compound used according to the invention canadvantageously be administered to the subject conjointly with an enzymeused for enzyme replacement therapy, in particular conjointly with arecombinant human acid α-glucosidase such as the recombinant enzyme soldunder the name Myozyme®. It then advantageously increases the efficacythereof.

In particular embodiments of the invention, in the general formula (I)R¹ and R² are independent from each other, in the sense that they arenot bonded to each other, in particular that they do not form together aring fused with the piperidine nucleus of the compound.

In particular, in the general formula (I):

-   -   R¹ then represents a hydrogen atom or a linear, branched and/or        cyclic hydrocarbon radical, saturated or unsaturated, aromatic        or not, optionally substituted, optionally comprising one or        more heteroatoms and/or one or more groups including at least        one heteroatom and optionally comprising a single ring or a        plurality of rings optionally fused,

and R² can represent a —CH(R³)—R⁴ group, wherein R³ and R⁴, which may beidentical or different, each represent a hydrogen atom or a linear,branched and/or cyclic hydrocarbon radical, saturated or unsaturated,aromatic or not, optionally substituted, optionally comprising one ormore heteroatoms and/or one or more groups including at least oneheteroatom and optionally comprising a single ring or a plurality ofrings optionally fused, R³ and R⁴ not simultaneously representing ahydrogen atom when R¹ represents a hydrogen atom.

In particular embodiments of the invention, R³ and R⁴ do notsimultaneously represent a hydrogen atom.

In particular embodiments of the invention, R¹ and R² are such that theydo not simultaneously represent, respectively, a propyl radical and anethyl radical. Preferentially, R³ and R⁴ are such that, when R¹ and R³each represent a hydrogen atom, R⁴ does not represent a phenyl radical.

In particular embodiments of the invention, R² represents a —CH(R³)—R⁴group, wherein R³ is as defined above and R⁴ represents a hydrocarbonradical, preferably comprising from 1 to 18, preferentially from 1 to 12and in particular from 1 to 6, carbon atoms, linear, branched and/orcyclic, saturated or unsaturated, aromatic or not, optionallysubstituted, optionally comprising a single ring or a plurality ofrings, optionally fused, and comprising one or more heteroatoms eachselected from oxygen, nitrogen, sulfur and silicon and/or one or moregroups including at least one heteroatom each selected from thecarbonyl, sulf oxide, sulfonyl and silane groups.

Otherwise, R¹ representing a hydrogen atom or a hydrocarbon radical,linear, branched and/or cyclic, saturated or unsaturated, aromatic ornot, optionally substituted, optionally comprising one or moreheteroatoms and/or one or more groups including at least one heteroatomand optionally comprising a single ring or a plurality of ringsoptionally fused, R² may represent a —(CHR⁷)—SO₂—Ar¹ group wherein Ar¹represents an aryl or heteroaryl radical, optionally substituted,comprising in particular from 5 to 18 atoms, and R⁷ represents ahydrogen atom or a hydrocarbon radical, preferably comprising from 1 to18, preferentially from 1 to 12 and in particular from 1 to 6, carbonatoms, linear, branched and/or cyclic, saturated or unsaturated,aromatic or not, optionally substituted, optionally comprising one ormore heteroatoms and/or one or more groups including at least oneheteroatom and optionally comprising a single ring or a plurality ofrings optionally fused. In particular embodiments of the invention, Ar¹represents an aromatic heterocycle, in particular a pyridine ring,optionally substituted, and/or R⁷ represents a hydrogen atom.

In particular embodiments of the invention, R¹ representing a hydrogenatom or a linear, branched and/or cyclic hydrocarbon radical, saturatedor unsaturated, aromatic or not, optionally substituted, optionallycomprising one or more heteroatoms and/or one or more groups includingat least one heteroatom and optionally comprising a single ring or aplurality of rings optionally fused, R² may represent a triazole group,optionally substituted.

In other variants of the invention, R¹ representing a hydrogen atom or alinear, branched and/or cyclic hydrocarbon radical, saturated orunsaturated, aromatic or not, optionally substituted, optionallycomprising one or more heteroatoms and/or one or more groups includingat least one heteroatom and optionally comprising a single ring or aplurality of rings optionally fused, R² represents a —(CH₂)₂—R⁸ group,wherein R⁸ represents:

-   -   a hydrogen atom;    -   a C1-C12 alkyl or cycloalkyl group, optionally comprising a        single ring or a plurality of fused rings, such as an adamantyl        group for example;    -   a —(CH₂)_(a)—OH group wherein a is an integer between 0 and 18,        preferably between 0 and 12 and in particular between 0 and 6;    -   a —(CH₂)_(b)—Ar₂ group wherein Ar² represents an aryl or        heteroaryl radical, optionally substituted, optionally        comprising one or more heteroatoms and/or one or more groups        including at least one heteroatom and optionally comprising a        single ring or a plurality of rings optionally fused, and b is        an integer between 0 and 18, preferably between 0 and 12 and in        particular between 0 and 6;    -   a —(CH₂)_(c)—Si(R⁹)₃ group wherein R⁹ represents a hydroxyl        radical, a C1-C4 alkyl radical, a C1-C4 alkoxyl radical or a        phenyl radical, and c is an integer between 0 and 18, preferably        between 0 and 12 and in particular between 0 and 6;    -   or a —(CH₂)_(d)—Z—R¹⁰ group wherein Z is a heteroatom selected        from oxygen, nitrogen and sulfur, R¹⁰ represents a hydrogen atom        or a C1-C18, preferably C1-C12 and in particular C1-C6, alkyl,        cycloalkyl, alkylaryl, aryl or acyl radical, said radical        optionally being interrupted and/or substituted by one or more        heteroatoms and/or one or more groups including at least one        heteroatom, in particular a sulfonyl radical, and d is an        integer between 0 and 18, preferably between 0 and 12 and in        particular between 0 and 6.

In particularly preferred embodiments of the invention, R¹ represents ahydrogen atom or a C1-C18, preferably C1-C6, for example C1-C3 and moreparticularly C1-C2, linear, branched and/or cyclic alkyl group, thisalkyl group optionally being interrupted and/or substituted by one ormore heteroatoms and/or one or more groups including at least oneheteroatom.

The compound used according to the invention can in particular complywith the general formula (I′a):

wherein:

R¹ represents a hydrogen atom or C1-C18, preferably C1-C6, linear,branched and/or cyclic alkyl group, optionally interrupted and/orsubstituted by one or more heteroatoms and/or one or more groupsincluding at least one heteroatom, and R⁸ represents:

-   -   a hydrogen atom;        -   a methyl, ethyl, propyl, butyl, pentyl, hexyl, cycloalkyl,            adamantyl, alkylcycloalkyl, alkylaryl or aryl radical, in            particular phenyl radical, said radical optionally being            interrupted and/or substituted by one or more heteroatoms            and/or one or more groups including at least one heteroatom;    -   a hydroxyl group;    -   a —Si(R¹²)₃ group wherein R¹² represents a hydroxyl radical, a        C1-C4 alkyl radical, a C1-C4 alkoxyl radical or a phenyl        radical;    -   a —(CH₂)_(f)—Y—R¹³ group wherein f is an integer between 0 and        6, Y is a heteroatom selected from oxygen, nitrogen and sulfur        and R¹³ represents a C1-C18, preferably C1-C12 and in particular        C1-C6, alkyl radical, or a C1-C18, preferably C1-C12 and in        particular C1-C6, aryl or heteroaryl radical;    -   a —(CH₂)_(g)—CO—R¹³ group wherein g is an integer between 0 and        6 and R¹³ is as defined above;    -   or a —(CH₂)_(h)—SO_(e)—R¹³ group wherein h is an integer between        0 and 6, e is equal to 1 or 2 and R¹³ is as defined above,

R⁸ not representing a hydrogen atom when R¹ represents a propyl radical.

In particular embodiments of the invention, the compound used complieswith the general formula (I″a):

wherein:

R¹ represents a hydrogen atom or a C1-C18 linear, branched and/or cyclicalkyl group, optionally interrupted and/or substituted by one or moreheteroatoms and/or one or more groups including at least one heteroatom,

R¹⁸ represents a linear, branched and/or cyclic hydrocarbon radical,saturated or unsaturated, aromatic or not, optionally substituted,comprising 4 to 18 carbon atoms, preferably 4 to 12 carbon atoms, and inparticular 5 to 12 carbon atoms, optionally comprising one or moreheteroatoms and/or one or more groups including at least one heteroatomand optionally comprising a single ring or a plurality of ringsoptionally fused.

R¹⁸ may in particular represent a butyl, pentyl, hexyl, cyclohexyl,phenyl, benzyl or adamantyl group.

Preferentially, in formula (1″a), R¹ represents a hydrogen atom.

Particular compounds that can be used according to the invention complywith the following formulae (IIa), (IIb), (IIb1), (IIb2), (IIb3),(IIb4), (IIb5), (IIb6), (IIb7), (IIc), (IIc1), (IId), (IIe), (IIo),(IIp), (IIp1), (IIq), (IIr), (IIs), (IIt), (IIu), (IIv), (IIw), (IIw1),(IIx), (IIx1), and (IIy):

In alternative embodiments of the invention, the compound used is suchthat, in the general formula (I), R¹ and R² form together, with theatoms of the piperidine ring to which each is attached, a 6-memberedheterocycle fused with the piperidine ring, optionally substituted byone or more radicals, which may be identical or different, each selectedfrom a hydroxyl group, an amino group, a carbonyl group or a carbonradical, preferably comprising from 1 to 18, preferentially from 1 to 12and in particular from 1 to 6, carbon atoms, linear, branched and/orcyclic, saturated or unsaturated, aromatic or not, optionallysubstituted, optionally comprising one or more heteroatoms and/or one ormore groups including at least one heteroatom and optionally comprisinga single ring or a plurality of rings optionally fused.

A particular compound that can be used according to the inventioncomplies with the formula (IIf):

In other embodiments of the invention, the compound used is such that,in the general formula (I), R¹ and R² form together, with the atoms ofthe piperidine ring to which each is attached, a 5-membered heterocyclefused with the piperidine ring, optionally substituted by one or moreradicals, which may be identical or different, each selected from ahydroxyl group, an amino group, a carbonyl group or a carbon radical,preferably comprising from 1 to 18, preferentially from 1 to 12 and inparticular from 1 to 6, carbon atoms, linear, branched and/or cyclic,saturated or unsaturated, aromatic or not, optionally substituted,optionally comprising one or more heteroatoms and/or one or more groupsincluding at least one heteroatom and optionally comprising a singlering or a plurality of rings optionally fused.

A particular compound that can be used according to the inventioncomplies with the formula (IIg):

In further alternative embodiments of the invention, the compound usedis such that, in the general formula (I), R¹ and R² form together, withthe atoms of the piperidine ring to which each is attached, a 4-memberedheterocycle fused with the piperidine ring, optionally substituted byone or more radicals, which may be identical or different, each selectedfrom a hydroxyl group, an amino group or a carbon radical, preferablyincluding from 1 to 18, preferentially from 1 to 12 and in particularfrom 1 to 6, carbon atoms, linear, branched and/or cyclic, saturated orunsaturated, aromatic or not, optionally substituted, optionallycomprising one or more heteroatoms and/or one or more groups includingat least one heteroatom and optionally comprising a single ring or aplurality of rings optionally fused.

The compound may in particular comply with the general formula (I′b):

wherein

R¹⁴ represents a hydrogen atom, a carbonyl radical or a C1-C18,preferably C1-C12 and in particular C1-C16, alkyl, alkenyl, alkynyl,alkylaryl or aryl radical, said radical optionally being interruptedand/or substituted by one or more heteroatoms and/or one or more groupsincluding at least one heteroatom, and R¹⁵ represents a hydrogen atom, ahydroxyl radical, an amino radical, or a C1-C18, preferably C1-C12 andin particular C1-C6, alkyl, alkenyl or aryl radical, said radicaloptionally being interrupted and/or substituted by one or moreheteroatoms and/or one or more groups including at least one heteroatom.Particular compounds that can be used according to the invention complyin particular with the formulae (IIh), (IIz1), (IIz2), (IIz3), (IIz4),and (IIz5):

In still alternative embodiments of the invention, the compound used issuch that, in the general formula (I), R¹ and R² form together, with theatoms of the piperidine ring to which each is attached, a 3-memberedheterocycle fused with the piperidine ring, optionally substituted by a—X—R⁵ group, wherein:

-   -   X represents a —C(═O)— or —CH(OR⁶)— radical wherein R⁶        represents a linear, branched and/or cyclic hydrocarbon radical,        saturated or unsaturated, aromatic or not, optionally        substituted, optionally comprising one or more heteroatoms        and/or one or more groups including at least one heteroatom and        optionally comprising a single ring or a plurality of rings        optionally fused, and R⁵ represents a hydrogen atom, an amino        group, or a linear, branched and/or cyclic hydrocarbon radical,        saturated or unsaturated, aromatic or not, optionally        substituted, optionally comprising one or more heteroatoms        and/or one or more groups including at least one heteroatom and        optionally comprising a single ring or a plurality of rings        optionally fused,    -   or X represents a —CH(OH)— radical and R⁵ represents a hydrogen        atom, or a linear, branched and/or cyclic hydrocarbon radical,        saturated or unsaturated, aromatic or not, optionally        substituted, optionally comprising one or more heteroatoms        and/or one or more groups including at least one heteroatom and        optionally comprising a single ring or a plurality of rings        optionally fused. In the latter configuration, in particular, R⁵        preferentially does not represent a non-substituted n-propyl        radical, a non-substituted c-hexyl radical or a non-substituted        phenyl radical.

The compound used according to the invention may in particular complywith the general formula (I′c):

wherein R¹⁶ represents a hydrogen atom or a C1-C18, preferably C1-C12and preferentially C1-C6, alkyl radical, said radical optionally beinginterrupted and/or substituted by one or more heteroatoms and/or one ormore groups including at least one heteroatom.

In particular, R¹⁶ may represent a —CH₂—OH group, a methyl radical or anethyl radical.

Particular compounds that can be used according to the invention complywith the formulae (IIj), (IIk), (IIm) and (IIn):

The invention can also be expressed in the terms of a method for thetherapeutic treatment of a subject suffering from or likely to contracta disease, in particular Pompe disease, this method comprising a step ofadministering to said subject in need thereof a therapeuticallyeffective amount of a compound complying with the general formula (I) orone of the pharmaceutically acceptable salts thereof. This method maycomply with one or more of the features described above in reference tothe therapeutic use of the compound of general formula (I), or one ofthe pharmaceutically acceptable salts thereof, as a drug.

The invention also relates to the use of a compound of general formula(I), or one of the pharmaceutically acceptable salts thereof, as definedabove, for manufacturing a drug, in particular a drug for treating Pompedisease.

According to another aspect, the present invention relates to apharmaceutical composition containing, as active principle, a compoundcomplying with the general formula (I) or one of the pharmaceuticallyacceptable salts thereof, in a pharmaceutically acceptable vehicle.

In the present description, “pharmaceutically acceptable vehicle” meansany vehicle useful for preparing a pharmaceutical composition and whichis generally safe, non-toxic and neither biologically nor otherwiseundesirable for the subject to be treated, in particular for mammals andespecially humans. The vehicle of the pharmaceutical compositionaccording to the invention may be either solid or semi-solid or liquid.It may be a diluent, an adjuvant or any other vehicle conventional initself for forming pharmaceutical compositions.

The pharmaceutical composition according to the invention may be in anygalenic form, in particular in a form adapted to administrationparenterally, intranasally, rectally, or by pulmonary or topical route.Preferentially, it is in a form suitable for oral administration. By wayof examples of such galenic forms, non-limitative of the invention,mention can be made of the forms of granules, powder, tablets, capsules,pills, syrup, solution or drinkable suspension, etc. The pharmaceuticalcomposition according to the invention may contain one or moreexcipients/additives conventional in themselves for formingpharmaceutical compositions, for example selected from preservatives,sweeteners, flavorings, fillers, disintegrators, wetting agents,emulsifiers, surfactants, dispersants, lubricants, stabilizers, buffers,antibacterial agents, antifungal agents, etc., or any one of themixtures thereof; and/or any compound allowing rapid, prolonged ordelayed, and/or targeted, release of the active principle afteradministration thereof to the subject.

The pharmaceutical composition according to the invention mayfurthermore contain one or more active principles other than thecompound of general formula (I) or one of the pharmaceuticallyacceptable salts thereof, these active principles being able or not toact synergically with said compound.

The pharmaceutical composition according to the invention is preferablyformulated in the form of unit doses.

The invention also relates to the therapeutic use of a pharmaceuticalcomposition according to the invention, as defined above, for treating adisease, in particular Pompe disease. This use may comply with one ormore of the features described above in reference to the therapeutic useof the compound of general formula (I) or of one of the pharmaceuticallyacceptable salts thereof.

According to another aspect, the present invention relates to a compoundcomplying with the following general formula (I′), this general formula(I′) defining a subfamily of the compounds of general formula (I)described above, or one of the pharmaceutically acceptable saltsthereof:

wherein:

-   -   R¹ represents a hydrogen atom or a linear, branched and/or        cyclic hydrocarbon radical, saturated or unsaturated, aromatic        or not, optionally substituted, optionally comprising one or        more heteroatoms and/or one or more groups including at least        one heteroatom and optionally comprising a single ring or a        plurality of rings optionally fused,

and R² represents a —CH(R³)—R⁴ group, wherein R³ and R^(4,) which may beidentical or different, each represent a hydrogen atom or a linear,branched and/or cyclic hydrocarbon radical, saturated or unsaturated,aromatic or not, optionally substituted, optionally comprising one ormore heteroatoms and/or one or more groups including at least oneheteroatom and optionally comprising a single ring or a plurality ofrings optionally fused, R³ and R⁴ being such that, when R¹ and R³ eachrepresent a hydrogen atom, R⁴ does not represent a hydrogen atom or aphenyl radical,

and R¹ and R² being such that they do not simultaneously representrespectively a propyl radical and an ethyl radical,

-   -   or R¹ and R² form together, with the atoms of the piperidine        ring to which each is attached, a 4-membered heterocycle fused        with the piperidine ring, optionally substituted by one or more        radicals, which may be identical or different, each selected        from a hydroxyl group, an amino group or a carbon radical,        preferably comprising from 1 to 18, preferentially from 1 to 12        and in particular from 1 to 6 carbon atoms, linear, branched        and/or cyclic, saturated or unsaturated, aromatic or not,        optionally substituted, optionally comprising one or more        heteroatoms and/or one or more groups including at least one        heteroatom and optionally comprising a single ring or a        plurality of rings optionally fused,    -   or R¹ and R² form together, with the atoms of the piperidine        ring to which each is attached, a 3-membered heterocycle fused        with the piperidine ring, optionally substituted by a —X—R⁵        group, wherein:        -   X represents a —C(═O)— or —CH(OR⁶)— radical wherein R⁶            represents a linear, branched and/or cyclic hydrocarbon            radical, saturated or unsaturated, aromatic or not,            optionally substituted, optionally comprising one or more            heteroatoms and/or one or more groups including at least one            heteroatom and optionally comprising a single ring or a            plurality of rings optionally fused, and R⁵ represents a            hydrogen atom, an amino group or a linear, branched and/or            cyclic hydrocarbon radical, saturated or unsaturated,            aromatic or not, optionally substituted, optionally            comprising one or more heteroatoms and/or one or more groups            including at least one heteroatom and optionally comprising            a single ring or a plurality of rings optionally fused;        -   or X represents a —CH(OH)— radical and R⁵ represents a            hydrogen atom or a hydrocarbon radical, for example            comprising from 1 to 6 carbon atoms, linear, branched and/or            cyclic, saturated or unsaturated, aromatic or not,            optionally substituted, optionally comprising one or more            heteroatoms and/or one or more groups including at least one            heteroatom and optionally comprising a single ring or a            plurality of rings optionally fused, R⁵ not representing an            n-propyl radical, a c-hexyl radical or a phenyl radical.            Here n-propyl radical, c-hexyl radical and phenyl radical            mean these radicals in non-substituted form. Thus, R⁵ may            represent a substituted n-propyl radical, a substituted            c-hexyl radical or a substituted phenyl radical.

In particular embodiments of the invention, the compound is such that,in the formula (I′):

R¹ represents a hydrogen atom or a linear, branched and/or cyclichydrocarbon radical, saturated or unsaturated, aromatic or not,optionally substituted, optionally comprising one or more heteroatomsand/or one or more groups including at least one heteroatom andoptionally comprising a single ring or a plurality of rings optionallyfused,

and R² represents a —CH(R³)—R⁴ group, wherein R³ is as defined above andR⁴ represents a hydrocarbon radical, preferably comprising from 1 to 18,preferentially from 1 to 12 and in particular from 1 to 6, carbon atoms,linear, branched and/or cyclic, saturated or unsaturated, aromatic ornot, optionally substituted, optionally comprising a single ring or aplurality of rings, optionally fused, and including one or moreheteroatoms each selected from oxygen, nitrogen, sulfur and siliconand/or one or more groups including at least one heteroatom eachselected from the carbonyl, sulfoxide, sulfonyl and silane groups; R⁴not representing a phenyl radical when R¹ and R³ each represent ahydrogen atom.

In particular, in the formula (I′), when R¹ represents a hydrogen atomor a linear, branched and/or cyclic hydrocarbon radical, saturated orunsaturated, aromatic or not, optionally substituted, optionallycomprising one or more heteroatoms and/or one or more groups includingat least one heteroatom and optionally comprising a single ring or aplurality of rings optionally fused, R² may represent a —(CHR⁷)—SO₂—Ar¹group wherein Ar¹ represents an aryl or heteroaryl radical, optionallysubstituted, preferably comprising from 5 to 18 atoms, and R⁷ representsa hydrogen atom or a hydrocarbon radical, preferably comprising from 1to 18, preferentially from 1 to 12 and in particular from 1 to 6, carbonatoms, linear, branched and/or cyclic, saturated or unsaturated,aromatic or not, optionally substituted, optionally comprising one ormore heteroatoms and/or one or more groups including at least oneheteroatom and optionally comprising a single ring or a plurality ofrings optionally fused.

The compound according to the invention may for example comply with thegeneral formula (I′d):

wherein R^(1,) R⁷ and Ar' are as defined above.

Otherwise, in the formula (I′), when R¹ represents a hydrogen atom or alinear, branched and/or cyclic hydrocarbon radical, saturated orunsaturated, aromatic or not, optionally substituted, optionallycomprising one or more heteroatoms and/or one or more groups includingat least one heteroatom and optionally comprising a single ring or aplurality of rings optionally fused, R² may represent a triazole group,optionally substituted.

The compound according to the invention may in particular comply withthe formula (I′e):

wherein R¹ is as defined above and R¹⁹ represents a hydrogen atom or aC1-C18 alkyl, alkylaryl, trialkylsilyl or aryl radical, said radicaloptionally being interrupted and/or substituted by one or moreheteroatoms and/or one or more groups including at least one heteroatom.

In variants of the invention, in the general formula (I′), R¹representing a hydrogen atom or a linear, branched and/or cyclichydrocarbon radical, saturated or unsaturated, aromatic or not,optionally substituted, optionally comprising one or more heteroatomsand/or one or more groups including at least one heteroatom andoptionally comprising a single ring or a plurality of rings optionallyfused, R² represents a —(CH₂)₂—R⁸ group, wherein R⁸ represents:

-   -   a hydrogen atom;    -   a C1-C12 alkyl or cycloalkyl group, optionally substituted,        optionally comprising a single ring or a plurality of fused        rings, such as an adamantyl radical;    -   a —(CH₂)_(a)—OH group wherein a is an integer between 0 and 18,        preferentially between 0 and 12 and in particular between 0 and        6; optionally, a may be different from 1 when R¹ represents a        hydrogen atom;    -   a —(CH₂)_(b)-Ar² group wherein Ar² represents an aryl or        heteroaryl radical, optionally substituted, optionally        comprising one or more heteroatoms and/or one or more groups        including at least one heteroatom and optionally comprising a        single ring or a plurality of rings optionally fused, and b is        an integer between 0 and 18, preferentially between 0 and 12 and        in particular between 0 and 6;

optionally, b may be different from 1 when R¹ represents a hydrogen atomand Ar² represents a phenyl radical;

-   -   a —(CH₂)_(b)—Si(R⁹)₃ group wherein R⁹ represents a hydroxyl        radical, a C1-C4 alkyl radical, a C1-04 alkoxyl radical or a        phenyl radical and c is an integer between 0 and 18,        preferentially between 0 and 12 and in particular between 0 and        6;    -   or a —(CH_(hd 2))_(d)—Z—R¹⁰ group wherein Z is a heteroatom        selected from oxygen, nitrogen and sulfur, R¹⁹ represents a        C1-C18, preferably C1-C12 and in particular C1-C6, alkyl,        cycloalkyl, alkylaryl, aryl or acyl radical, said radical        optionally being interrupted and/or substituted by one or more        heteroatoms and/or one or more groups including at least one        heteroatom, such as a sulfonyl group, and d is an integer        between 0 and 18, preferentially between 0 and 12 and in        particular between 0 and 6.

In particularly preferred embodiments of the invention, R¹ represents aC1-C18, preferably C1-C6, linear, branched and/or cyclic alkyl group,optionally interrupted and/or substituted by one or more heteroatomsand/or more groups including at least one heteroatom.

The compound according to the invention may for example comply with thegeneral formula (I′a):

wherein:

R¹ represents a hydrogen atom or a C1-C18, preferably C1-C12, inparticular

C1-C6, for example C1-C3 and more particularly C1-C2, linear, branchedand/or cyclic alkyl group, said alkyl group optionally being interruptedand/or substituted by one or more heteroatoms and/or one or more groupsincluding at least one heteroatom,

R⁸ represents:

-   -   a hydrogen atom;    -   a hydroxyl group;        -   a methyl, ethyl, propyl, butyl, pentyl, hexyl, cycloalkyl,            adamantyl, alkylcycloalkyl, alkylaryl or aryl radical, said            radical optionally being interrupted and/or substituted by            one or more heteroatoms and/or one or more groups including            at least one heteroatom;    -   a —Si(R¹²)₃ group wherein R¹² represents a hydroxyl radical, a        C1-C4 alkyl radical, a C1-C4 alkoxyl radical or a phenyl        radical;    -   a —(CH₂)_(f)—Y—R¹³ group wherein f is an integer between 0 and        6, Y is a heteroatom selected from oxygen, nitrogen and sulfur        and R¹³ represents a C1-C18, preferably C1-C12 and in particular        C1-C6, alkyl radical, or an aryl or heteroaryl radical,        preferably C1-C18, preferably C1-C12 and in particular C1-C6;    -   a —(CH₂)_(g)—CO—R¹³ group wherein g is an integer between 0 and        6 and R¹³ is as defined above;    -   or a —(CH₂)_(h)—SO_(e)—R¹³ group wherein h is an integer between        0 and 6 and e is equal to 1 or 2, and R¹³ is as defined above;

R⁸ not representing a hydrogen atom when R¹ represents a propyl radical.The compound according to the invention may comply with the generalformula (I″a):

wherein

R¹ represents a hydrogen atom or a C1-C18 linear, branched and/or cyclicalkyl group, optionally interrupted and/or substituted by one or moreheteroatoms and/or one or more groups including at least one heteroatom,

R¹⁸ represents a linear, branched and/or cyclic hydrocarbon radical,saturated or unsaturated, aromatic or not, optionally substituted,comprising from 4 to 18 carbon atoms, preferably from 4 to 12 carbonatoms, and preferentially from 5 to 12 carbon atoms, optionallycomprising one or more heteroatoms and/or one or more groups includingat least one heteroatom and optionally comprising a single ring or aplurality of rings optionally fused.

R¹⁸ may in particular represent a butyl, pentyl, hexyl, cyclohexyl,phenyl, benzyl or adamantyl group.

Particular compounds according to the invention are the compounds offormulae (IIa), (IIb), (IIb1), (IIb2), (IIb3), (IIb4), (IIb5), (IIb6),(IIb7), (IIc), (IIc1), (IId), (IIo), (IIp), (IIp1), (IIq), (IIr), (IIs),(IIt), (IIu), (IIv), (IIw), (IIw1), (IIx), (IIx1), and (IIy) describedabove.

In alternative embodiments of the invention, the compound complies withthe general formula (I′b):

wherein

R¹⁴ represents a hydrogen atom, a carbonyl radical or an alkyl, alkenyl,alkynyl, or alkylaryl radical, such as a benzyl or a C1-C18, preferablyC1-C12 and in particular C1-C6, aryl radical, said radical optionallybeing interrupted and/or substituted by one or more heteroatoms and/orone or more groups including at least one heteroatom; an example of sucha radical complies with the formula —CH₂-TMS, where TMS represents atrimethylsilyl residue;

and R¹⁵ represents a hydrogen atom, a hydroxyl radical, an amino radicalor a C1-C18, preferably C1-C12 and in particular C1-C6, alkyl, alkenylor aryl radical, said radical optionally being interrupted and/orsubstituted by one or more heteroatoms and/or one or more groupsincluding at least one heteroatom.

Particular compounds complying with this definition are the compounds offormulae (IIh), (IIz1), (IIz2), (IIz3), (IIz4) and (IIz5) describedabove.

In other variants of the invention, the compound complies with thegeneral formula (I′c):

wherein R¹⁶ represents a hydrogen atom or a C1-C18, preferably C1-C12and preferentially C1-C6, alkyl radical, said radical optionally beinginterrupted and/or substituted by one or more heteroatoms and/or one ormore groups including at least one heteroatom.

In particular, R¹⁶ may represent a —CH₂—OH group, a methyl radical or anethyl radical.

Particular compounds complying with this definition are the compounds offormulae (IIj) and (IIk) described above.

All the compounds according to the invention, complying with the generalformula (I′), can advantageously be used as drugs in accordance with thepresent invention, in particular for treating Pompe disease.

The compounds of general formula (I) used according to the invention, inparticular the compounds complying with the general formula (I′) asdefined above, can be synthesized by any method conventional per se fora person skilled in the art. It falls in particular within thecompetence of a person skilled in the art to determine, for eachparticular compound, which starting products to use and which synthesismethod to apply.

The present invention furthermore relates to novel synthesis methods,which have been developed by the inventors for preparing compounds ofgeneral formula (I), and in particular of general formula (I′).

Some of the preparation methods according to the invention make itpossible to obtain compounds of general formula (I′) wherein R¹ and R²are independent from one another, in particular complying with thegeneral formula (I′a) or with the general formula (I″a) as above.

One example of such a particular preparation method according to theinvention comprises successive steps of:

a/ reacting a compound of general formula (III) or (IV):

wherein Bn represents a benzyl radical,

with a compound of general formula (V):

wherein R⁸ is as defined above with reference to the compound of generalformula (I′) according to the invention, R⁸ however representing neithera hydrogen atom nor a hydroxyl group —OH, nor an amino group —NH₂, inthe presence of an organometallic compound,

b/ optionally, reducing the hydroxylamine function into amine,

c/ optionally, alkylation of the nitrogen atom of the piperidine ring,

d/ and hydrogenolysis of the product obtained at the end of step whereapplicable step b/ or step c/, in particular for achieving the cleavageof the benzyl radicals to form hydroxyl groups, and where applicable thetransformation of the hydroxylamine function into amine and thehydrogenation of the triple bond.

The organometallic compound used for the step a/ may be an organozinc,organolithium, organomagnesium, organoalane, organocopper, etc.compound, or any one of the mixtures thereof. Preferentially, in stepa/, the reaction is implemented in the presence of dialkylzinc, inparticular diethylzinc Et₂Zn, or butyllithium.

More generally, the organometallic compound may comply with the generalformula (VII):

R¹⁷-M  (VII)

wherein

R¹⁷ represents a C1-C18 alkyl, alkenyl, alkynyl, alkylaryl or arylradical, said radical optionally being interrupted and/or substituted byone or more heteroatoms and/or one or more groups including at least oneheteroatom, and M represents a metal element such as lithium, zinc,copper, aluminum or magnesium, or M represents Mg—X², where X²represents a halogen atom.

The step b/ of reducing the hydroxylamine function into amine and thestep c/ of N-alkylation can be implemented according to any methodconventional per se for a person skilled in the art.

The step d/ of hydrogenolysis may also be performed by any methodconventional per se for a person skilled in the art, in particular bycatalytic hydrogenation.

Entirely surprisingly and advantageously, such a method makes itpossible to prepare compounds of general formula (I′), in particular ofgeneral formula (I′a) or of general formula (I″a), completelystereoselectively.

Examples of such methods can be represented by the synthesis schemes 1shown on FIG. 1 , for the particular example of a compound complyingwith the general formula (I′a).

Compounds of general formula (I′a) or (I″a) may otherwise, for example,be prepared by a method comprising successive steps of:

a/ cycloaddition reaction of a compound of general formula (III) withtrimethylsilylacetylene,

b/ reaction of the cycloadduct obtained with a fluoride such astetrabutylammonium fluoride, for example by a protocol similar to theone described in the publication of Ahn, et al., 1994, J. Org. Chem. 59:6282-6286,

c/ reduction by a metal hydride such as boron and sodium hydride(NaBH₄), lithium and aluminum hydride (LiAlH₄) or diisobutylaluminumhydride (DIBAL-H), or by a borane such as a dimethylsulfide-boranecomplex (BH₃Me₂S), a borane-tetrahydrofuran complex (BH₃THF), aborane-pyridine complex (BH₃pyridine), diborane B₂H₆, lithium andaluminum hydride (LiAIH₄) being particularly preferred,

d/ optionally, a step of O-alkylation, O-acylation or O-sulfonylation,which can be implemented according to any method conventional per se fora person skilled in the art,

e/ optionally, a step of N-alkylation, which can be implementedaccording to any method conventional per se for a person skilled in theart,

f/ and hydrogenolysis of the product obtained at the end of step c/,where applicable step d/ or step e/, in particular for implementing thecleavage of the benzyl radicals to form hydroxyl groups.

This synthesis method is particularly advantageous in that:

-   -   the step a/ is simple to implement and completely regio- and        diastereoselective in favor of a product of D-gluco        configuration;    -   the cycloadduct formed in step a/ is easily and effectively        transformed into β-lactam, itself easily and effectively reduced        into piperidine-alcohol (the β-lactam obtained may otherwise be        transformed into a saturated 4-membered ring, by reduction by a        silane or by reducing alkylation in the presence of metal        catalysts). One example of such a method can be represented by        the synthesis scheme 2 shown on FIG. 2 for the particular        example of a compound complying with the general formula Il′a).

Compounds of formula (I′d) above can be prepared by a method comprisingthe reaction of a compound of formula (III) or (IV) as above with acompound of general formula (VI):

in the presence of a lithiated base such as lithium diisopropylamide(LDA) or lithium bis(trimethylsilyl)amide (LiHMDS), preferably in thepresence of LiHMDS at low temperature, preferably −78° C.; then, afteroptionally a step of reducing the hydroxylamine function into amine, andoptionally a step of alkylation of the nitrogen atom of the piperidinering, hydrogenolysis of the product obtained.

An example of such a method can be represented by the synthesis scheme 3shown in FIG. 3 , for the particular example of a compound complyingwith the general formula (I′d).

Compounds of general formula (I) and in particular of general formula(I′) can otherwise, for example, be prepared, from compounds of formula(III) or (IV), by a method comprising the successive steps of:

-   -   a/ reaction with a compound of general formula (VII), in        particular in the presence of a Lewis acid:

R¹⁷-M  (VII)

wherein

R¹⁷ represents a C1-C18 alkyl, alkenyl, alkynyl, alkylaryl or arylradical, said radical optionally being interrupted and/or substituted byone or more heteroatoms and/or one or more groups including at least oneheteroatom, and M represents a metal element such as lithium, zinc,copper, aluminum or magnesium, or M represents Mg—X², where X²represents a halogen atom.

-   -   b/ then, optionally, reduction of the hydroxylamine function        into amine, in accordance with any method conventional per se        for a person skilled in the art, in particular by treatment with        zinc powder in an acid medium,    -   c/ then, optionally, alkylation of the nitrogen atom of the        piperidine ring, by any method conventional per se for a person        skilled in the art,    -   d/ then, optionally, a step of cyclizing metathesis of olefins        catalyzed by a complex based on ruthenium, preferentially the        2nd generation Grubbs catalyst,    -   e/ and finally, hydrogenolysis of the product obtained at the        end of step a/, where applicable at the end of step b/, of step        c/, or of step d/, according to any method conventional per se        for a person skilled in the art, in particular in the presence        of hydrogen and of a catalytic quantity of palladium on carbon,        in an acid medium.

The synthesis route used for obtaining compounds complying with thegeneral formula (I) falls under the general synthesis scheme 4 shown onFIG. 4 .

Other preparation methods according to the invention make it possible toobtain compounds of general formula (I′) wherein R¹ and R² formtogether, with the atoms of the piperidine ring to which each isattached, a 4-membered heterocycle fused with the piperidine ring.

Examples of such methods comprise successive steps of:

-   -   a/ cycloaddition reaction of a compound of general formula (III)        with trimethylsilylacetylene, followed by a reaction with a        fluoride such as tetrabutylammonium fluoride, for example        according to a protocol similar to the one previously described        in the publication by Ahn, et al., 1994, J. Org. Chem. 59:        6282-6286; then    -   either b/ reduction of β-lactam carbonyl by a silane such as        phenylsilane PhSiH₃, in the presence of a catalyst based on        rhodium such as [Rh(COD)₂]BF₄ and of        1,3-bis(diphenylphosphino)propane, according to a protocol        similar to the one previously described in the publication by        Bornschein et al., 2015, Eur. J. Org. Chem, 1915-1919;

or b′/ reducing alkylation of β-lactam carbonyl by reaction withtetramethyldisiloxane in the presence of Vaska's catalyst at ambienttemperature, and then addition of a compound of formula (VII) as definedabove, at −78° C., according to a protocol similar to the one describedin the publication by Xie and Dixon, 2017, Chem. Sci. 8: 7492-7497;

and finally

-   -   c/ hydrogenolysis of the product obtained at the end of step b/        or b′/, in particular for cleavage of the benzyl radicals to        form hydroxyl groups.

The step c/ of hydrogenolysis can be implemented according to any methodconventional per se for a person skilled in the art, in particular bycatalytic hydrogenation.

The steps b/ and b′/ are particularly advantageous, and novel, in thatthey make it possible to implement the reduction or the reducingalkylation of a β-lactam the nitrogen atom of which is included in apiperidine ring, to form a heterocycle of the conidine type.

Examples of such methods can be represented by the synthesis scheme 5shown on FIG. 5 , for the particular example of a compound complyingwith the general formula (I′b).

Another example of such a method comprises successive steps of:

a/ Kinugasa reaction, as described in the reviews by Stecko et al.,2014, Tetrahedron 70: 7817-7844 or by Khangarot & Kaliappan, 2013, Eur.J. Org. Chem. 7664-7677, of a compound of general formula (III) with acompound of general formula (VIII):

wherein R¹⁵ represents a C1-C18 alkyl, alkenyl or aryl radical,optionally interrupted and/or substituted by one or more heteroatomsand/or one or more groups including at least one heteroatom, in thepresence of a Cu(I) salt and an amine; then

b/ reducing alkylation of β-lactam carbonyl by reaction withtetramethyldisiloxane in the presence of Vaska's catalyst at ambienttemperature, then addition of a compound of formula (VII) as definedabove, at −78° C., according to a protocol similar to the one describedin the publication by Xie and Dixon, 2017, Chem. Sci. 8: 7492-7497; andfinally

c/ hydrogenolysis of the product obtained at the end of the step b/, inparticular for implementing the cleavage of the benzyl radicals to formhydroxyl groups. The step c/ of hydrogenolysis can be implementedaccording to any method conventional per se for a person skilled in theart, in particular by catalytic hydrogenation.

Step b/ is particularly advantageous, and novel, in that it makes itpossible to implement the reducing alkylation of a β-lactam the nitrogenatom of which is included in a piperidine ring, to form a heterocycle ofthe conidine type.

An example of such a method can be represented by the synthesis scheme 6shown on FIG. 6 , for the particular example of a compound complyingwith the general formula (I′b).

Other preparation methods according to the invention make it possible toobtain compounds of general formula (I′) wherein R¹ and R² formtogether, with the atoms of the piperidine ring to which each isattached, a 3-membered heterocycle fused with the piperidine ring.

An example of such a method comprises successive steps of:

a/ cycloaddition reaction of a compound of general formula (111) or of acompound of general formula (III′):

wherein Ac represents an acetyl radical,

with a compound of general formula (V) as described above, wherein R⁸ isas defined above with reference to the compound of general formula (I′)according to the invention, R⁸ however representing neither a hydrogenatom nor a hydroxyl group —OH, nor an amino radical —NH₂,

-   -   b/ thermal Baldwin rearrangement, according to a protocol        similar to the one described in the publication by Tangara et        al., 2017, Org. Lett. 19: 4842-4845, making it possible to form        an acylaziridine, this step preferentially being implemented at        110° C. under irradiation by microwave radiation,    -   c/ reduction of the acylaziridine carbonyl thus obtained by        reaction with a metal hydride, preferentially LiAIH₄ or NaBH₄,    -   d/ and debenzylation, according to any method conventional per        se for a person skilled in the art, in particular by Birch        reduction in the presence of metals dissolved in liquid ammonia        at low temperature, preferably at −78° C., the metal used        preferably being lithium.

An example of such a method can be represented by the synthesis scheme 7shown in FIG. 7 , for the particular example of compounds complying withthe general formula (I′c).

An example of a method for preparing compounds of general formula (I′e)as above can be represented by the synthesis scheme 8 shown on FIG. 8 ,with R²⁰ being identical to R¹⁹, R²⁰ however not representing a hydrogenatom.

BRIEF DESCRIPTION OF THE DRAWINGS

The features and advantages of the invention will emerge more clearly inthe light of the following example embodiments, provided by simple wayof illustration and in no way !imitative of the invention, with thesupport of FIGS. 1 to 8 , wherein:

FIG. 1 shows a first example of general synthesis schemes (synthesisscheme 1) for preparing compounds of formula (I′a) according to theinvention.

FIG. 2 shows a second example of a general synthesis scheme (synthesisscheme 2) for preparing compounds of formula (I′a) according to theinvention.

FIG. 3 shows an example of a general synthesis scheme (synthesis scheme3) for preparing compounds of formula (I′d) according to the invention.

FIG. 4 shows a third example embodiment of general synthesis schemes(synthesis schemes 4) for preparing compounds of formula (I′a) and, moregenerally, compounds of general formula (I) used according to theinvention.

FIG. 5 shows first examples of general synthesis schemes (synthesisschemes 5) for preparing compounds of formula (I′b) according to theinvention.

FIG. 6 shows a second example of general synthesis schemes (synthesisschemes 6) for preparing compounds of formula (I′b) according to theinvention.

FIG. 7 shows an example of general synthesis schemes (synthesis schemes7) for preparing compounds of formula (I′c) according to the invention.

FIG. 8 shows an example of a general synthesis scheme (synthesis scheme8) for preparing compounds of formula (I′e) according to the invention.

DESCRIPTION OF THE PREFERRED EMBODIMENTS A/ Synthesis andCharacterization of Compounds Used in Accordance With the Invention

All the reactions were conducted under inert atmosphere in previouslydried glassware, under stirring by a magnetic bar, the assembly beingplaced above a magnetic stirrer, except in the case of reactions underirradiation by microwave. The latter were implemented in sealed tubesequipped with a magnetic bar placed in a microwave reactor, at atemperature regulated by an internal infrared probe. The toluene, theether and the dichloromethane used as reaction solvents were previouslyfiltered on an Inert PureSolv® purification system. The acetonitrile anddichloroethane were distilled on CaH₂. The THF was distilled on sodiumin the presence of benzophenone. The commercial reagents, the methanoland the ethanol were used without purification. The reactions werefollowed by thin-layer chromatography (TLC) by means of silica onaluminum plates (Merck, Kieselgel 60 F254), with revelation underultraviolet radiation and then by a 3% solution of potassiumpermanganate in a 10% solution of potassium hydroxide (w/v). Thepurifications by column chromatography were implemented by means ofMacherey-Nagel® Silica Gel 60 (70-230 mesh). The rotatory powers weremeasured on a PerkinElmer 341 polarimeter. The infrared spectra wereobtained on a Nicolet “Magna 550” spectrometer including an ATR(attenuated total reflexion) module on which the products were depositedpure, in the solid or liquid state. The data are expressed in cm⁻¹. The¹H NMR and ¹³C NMR {DEPT-Q} were obtained with Avance 500 (¹H: 500 MHz,¹³C: 125 MHz) or Avance 400 (1H: 400 MHz, ¹³C: 100 MHz) spectrometers.The chemical shifts for the ¹H spectra are expressed with respect tothose of the residual solvents contained in CDCl₃ (δ7.26 ppm) or CD₃OD(δ 3.31 ppm). The chemical shifts for the ¹³C spectra are expressed withrespect to those of the solvents CDCl₃ (δ 77.16 ppm) or CD₃OD (δ 49.00ppm). The ¹H NMR spectra are reported as follows: chemical shift (ppm),multiplicity (br: broad; s: singulet; d: doublet; dd: doublet ofdoublets; t: triplet; pst: pseudo triplet; m: multiplet), couplingconstants (Hz) and integration. The high-resolution mass spectra (HRMS)were recorded on a Thermo Scientific ESI/LTQ Orbitrap XL® or Waters G2-SQ-TOF mass spectrometer.

A.1/Synthesis Methods 1

The synthesis methods used for obtaining compounds complying with theabove general formula (I′a) falls under the general synthesis schemesshown on FIG. 1 .

1) General Protocol A—Alkynylation of the Nitrone of Formula (III)Leading to the Propargylic Hydroxylamines of Formula A-1

A 1M solution of diethyl zinc in hexane (1.5 equiv.) is added dropwiseto an alkyne solution of formula (V) (4 equiv.) in anhydrous toluene at0° C. under argon atmosphere. The resulting mixture is stirred for 30minutes at 0° C. A solution of ketonitrone of formula (III) (1 equiv.)in anhydrous toluene is then added dropwise at 0° C., and then thereaction mixture is stirred until the reaction is complete (followed byTLC). A saturated aqueous solution of NaHCO₃ is added and then theresulting mixture is diluted with diethylether. The organic phase isseparated and the aqueous phase is extracted twice with diethylether.The organic phases are washed with brine, dried on MgSO₄ and evaporatedunder reduced pressure. The hydroxylamines of formula A-1 thus formedare purified by silica gel chromatography, before being reduced anddebenzylated in accordance with the following general protocol B.

2) General Protocol A′—Alkynylation of the Nitrone of Formula (III)Leading to the Propargylic Hydroxylamines of Formula A-1.

A 1.4 M solution of n-butyllithium in hexane (2.5 equiv.) is addeddropwise to a solution of alkyne of formula (V) (2.5 equiv.) inanhydrous THF at −10° C. under argon atmosphere. The resulting solutionis stirred for 15 minutes at −10° C. and is then cooled to −78° C. Asolution of ketonitrone of formula (III) (1 equiv.) in anhydrous THF isthen added dropwise at −78° C., and then the reaction mixture is stirreduntil the reaction is complete (followed by TLC). A saturated aqueoussolution of NH₄Cl is added and the mixture is allowed to rise to ambienttemperature, and then extracted three times by ethyl acetate. Theorganic phases are collected and washed with brine, dried on MgSO₄ andconcentrated under reduced pressure. The hydroxylamines of formula A-1thus isolated are purified by silica gel chromatography, before beingreduced and debenzylated in accordance with the following generalprotocol B.

3) General Protocol B

1.5 equiv. of hydrochloric acid HCI (2M solution in anhydrous ether) and0.2 equiv. of Pd/C 10% are added to a solution of O-benzylatediminosugar (1 equiv.) in absolute ethanol. The suspension obtained isstirred at room temperature for 17 hours under pressure of hydrogen (5bar) and then filtered on Celite®. The Celite® is rinsed with methanoland the filtrate is concentrated at reduced pressure to give animinosugar hydrochlorate. This salt is purified on Dowex® 50W-X2 ionexchange resin previously activated by HCI, and eluted with aqueousNH₄OH, to obtain after evaporation of the solvents the correspondingneutral compound of formula (I′a).

Compound of Formula (IIc)

The compound of above formula (IIc)((2R,3R,4R,5S)-2-(hydroxymethyl)-2-phenethylpiperidine-3,4,5-triol: 36.7mg; 73% for 2 steps) was prepared in accordance with the generalprocedures A and B, from nitrone of formula (III) (110.0 mg, 0.205 mmol)and phenylacetylene (Va: R⁸=Ph, 0.034 mL; 0.307 mmol).

A solid yellow is obtained, with the following characteristics:

[α]²⁰ _(D)+4.7 (c 0.98, CH₃OH);

IR v 3291, 2918, 2864, 1632, 1494, 1455, 1363, 1270, 1198, 1094, 1076,1040, 1004 cm⁻¹;

¹H NMR (500 MHz, CD₃OD) δ 7.31-7.08 (m, 5H), 3.73 (d, J=10.4 Hz, 1H),3.55 (d, J=10.5 Hz, 1H), 3.55-3.43 (m, 2H), 3.45-3.34 (m, 1H), 3.00-2.90(m, 1H), 2.68-2.51 (m, 3H), 1.91-1.72 (m, 2H) ppm;

¹³C NMR (125 MHz, CD₃OD) δ 144.4 (^(Ar)Cq), 129.4 ^((Ar)CH), 129.3(^(Ar)CH), 126.7(^(Ar)CH), 76.5 (CH), 75.2 (CH), 73.8 (CH), 65.6 (CH₂),60.5 (Cq), 45.9 (CH₂), 30.7 (CH₂), 29.9 (CH₂) ppm;

HRMS (ESI⁺) Calc. C₁₄H₂₂NO₄ [M+H]⁺: m/z=268.15433; Found m/z=268.15372.

Compound (IIx1)

The compound of above formula (IIx1)((2R,3R,4R,5S)-2-(hydroxymethyl)-2-(2-(trimethylsilyl)ethyl)piperidine-3,4,5-triol:7.1 mg; 29% for 2 steps) was prepared in accordance with the generalprocedures A and B, from nitrone of formula (III) (102.1 mg, 0.189 mmol)and trimethylsilylacetylene (Vb: R⁸=TMS, 0.105 mL; 0.759 mmol).

A white foam is obtained, with the following characteristics:

[hd]²⁰D+4.51 (c 0.71, MeOH);

¹H NMR (400 MHz, CD₃OD) δ 3.57 (d, J=10.9 Hz, 1H), 3.52 (d, J=9.3 Hz,1H), 3.44 (t, J=4.0 Hz, 1H), 3.39 (d, J=10.0 Hz, 1H), 3.39-3.33 (m, 1H),2.85 (dd, J=12.8, 5.5 Hz, 1H), 2.42 (dd, J=12.8, 10.8 Hz, 1H), 1.62-1.51(m, 2H), 0.56-0.44 (m, 1H), 0.39-0.29 (m, 1H), 0.02 (s, 9H) ppm;

¹³C NMR (100 MHz, CD₃OD) δ 76.6 (CH), 75.5 (CH), 73.8 (CH), 65.6 (CH₂),60.5 (Cq), 45.8 (CH₂), 21.0 (CH₂), 8.60 (CH₂), −1.86 (CH₃) ppm;

HRMS (ESI⁺) Calc. C₁₁H₂₆NO₄Si [M+H]⁺: m/z=264.16256; Foundm/z=264.16282.

Compound (IIr)

The compound of above formula (IIr)((2R,3R,4R,5S)-2-(2-((3R,5R,7R)-adamantan-1-ypethyl)-2-(hydroxymethyl)piperidine-3,4,5-triol:15.0 mg; 27% for 2 steps) was prepared in accordance with the generalprocedures A′ and B, from nitrone of formula (III) (100 mg, 0.185 mmol)and adamantylacetylene (Vh: R⁸=adamantyl, 74.5 mg, 0.465 mmol).

A yellowish lacquer is obtained, with the following characteristics:

[α]²⁰ _(D)+7.46 (c 0.63, MeOH);

¹H NMR (500 MHz, CD₃OD) δ 3.79 (d, J=10.9 Hz, 1H), 3.64-3.48 (m, 4H),3.11 (br d, J=11.3 Hz, 1H), 2.78-2.66 (m, 1H), 2.00-1.91 (m, 3H),1.82-1.63 (m, 8H), 1.58-1.49 (m, 6H), 1.19-1.03 (m, 2H) ppm;

¹³C NMR (100 MHz, CD₃OD) δ 74.9 (CH), 72.5 (CH), 70.8 (CH), 63.7 (Cq),62.5 (CH₂), 44.2 (CH₂), 43.3 (CH₂), 38.2 (CH₂), 37.0 (CH₂), 30.1 (CH),20.7 (CH₂) ppm;

HRMS (ESI⁺) Calc. C₁₈H₃₁NO₄ [M+H]⁺: m/z=326.23258; Found m/z=326.23225.

Compound (IIb7)

The compound of above formula (IIb7)((2R,3R,4R,5S)-2-(2-cyclohexylethyl)-2-(hydroxymethyl)piperidine-3,4,5-triol:57.3 mg; 59% for 2 steps) was prepared in accordance with the generalprocedures A and B, from nitrone of formula (III) (99.8 mg; 0.185 mmol)and 1-ethynylcyclohexene (Vd: R⁸=cyclohexene; 87 μL; 0.742 mmol).

A white solid is obtained, with the following characteristics:

[α]²⁰ _(D)+3.63 (c 1.43, MeOH);

¹H NMR (400 MHz, CD₃OD) δ 3.60 (d, J=10.6 Hz, 1H, ⁷CH₂), 3.52-3.43 (m,2H, ³CH, ⁴CH), 3.43-3.33 (m, 2H), 2.87 (dd, J=12.8, 5.0 Hz), 2.49 (ps t,J=11.7 Hz, 1H), 1.83-1.62 (m, 5H), 1.60-1.47 (m, 2H), 1.34-1.06 (m, 6H),1.01-0.86 (m, 2H) ppm;

¹³C NMR (100 MHz, CD₃OD) δ 76.5 (CH), 75.1 (CH), 73.8 (CH), 65.5 (CH₂),60.3 (Cq), 45.8 (CH₂), 39.9 (CH), 34.6 (CH₂), 34.5 (CH₂), 30.6 (CH₂),27.8 (CH₂), 27.5 (CH₂), 24.8 (CH₂) ppm;

HRMS (ESI⁺) Calc. C₁₄H₂₀NO₄ [M+H]⁺: m/z=274.20128; Found m/z=274.20139.

Compound (IIb1)

The compound of above formula (IIb1)((2R,3R,4R,5S)-2-(hydroxymethyl)-2-pentylpiperidine-3,4,5-triol: 32.8mg; 67% for 2 steps) was prepared in accordance with the generalprocedures A and B, from nitrone of formula (III) 96.8 mg; 0.180 mmol)and 1-pentyne (Ve: R⁸=C₃H₇; 71 μL; 0.720 mmol).

A yellow solid is obtained, with the following characteristics:

[α]²⁰ _(D)−1.29 (c 1.01, MeOH);

¹H NMR (400 MHz, CD₃OD) δ 3.61 (d, J=10.6 Hz, 1H), 3.52-3.33 (m, 4H),2.87 (dd, J=12.8, 5.3 Hz, 1H), 2.49 (ps t, J=11.8 Hz, 1H), 1.62-1.43 (m,2H), 1.43-1.17 (m, 6H), 0.92 (t, J=6.7 Hz, 3H) ppm;

¹³C NMR (100 MHz, CD₃OD) δ 76.5 (CH), 75.2 (CH), 73.9 (CH), 65.7 (CH₂),60.2 (Cq), 45.9 (CH₂), 33.9 (CH₂), 27.7 (CH₂), 23.6 (CH₂), 22.9 (CH₂),14.4 (CH₃) ppm; HRMS (ESI⁺) Calc. C₁₁H₂₄NO₄ [M+H]+: m/z=234.16998; Foundm/z=234.17004.

Compound (IIb3)

The compound of above formula (IIb3)((2R,3R,4R,5S)-2-heptyl-2-(hydroxymethyl)piperidine-3,4,5-triol: 33.2mg; 69% for 2 steps) was prepared in accordance with the generalprocedures A and B, from nitrone of formula (III) (100.7 mg; 0.187 mmol)and 1-heptyne (Vf: R⁸=C₅H₁₁; 98 μL; 0.749 mmol).

A yellow solid is obtained, with the following characteristics:

[α]²⁰ _(D)+1.04 (c 0.96, MeOH);

1H NMR (400 MHz, CD₃OD) δ 3.61 (d, J=10.6 Hz, 1H), 3.51-3.44 (m, 2H),3.41 (d, J=10.8 Hz), 3.39-3.33 (m, 1H), 2.87 (dd, J=13.0, 5.4 Hz, 1H),2.49 (ps t, J=11.4 Hz, 1H), 1.58-1.47 (m, 2H), 1.43-1.18 (m, 10H), 0.90(t, J=6.2 Hz, 3H) ppm;

¹³C NMR (100 MHz, CD₃OD) δ 76.5 (CH), 75.1 (CH), 73.8 (CH), 65.6 (CH₂),60.3 (Cq), 45.9 (CH₂), 33.0 (CH₂), 31.7 (CH₂), 30.4 (CH₂), 23.7 (CH₂),23.2 (CH₂), 27.8 (CH₂), 14.4 (CH₃) ppm;

HRMS (ESI⁺) Calc. C₁₃H₂₈NO₄ [M+H]⁺: m/z=261.20128; Found m/z=261.20131.

Compound (IIc1)

The compound of above formula (IIc1)((2R,3R,4R,5S)-2-(hydroxymethyl)-2-(3-phenylpropyl)piperidine-3,4,5-triol:20.2 mg; 45% for 2 steps) was prepared according to the generalprocedures A and B, from nitrone of formula (III) (96.7 mg; 0.179 mmol)and 3-phenyl-1-propyne (Vg: R⁸=CH₂Ph; 89 μL; 0.719 mmol). A yellowlacquer is obtained, with the following characteristics:

[α]²⁰ _(D)+1.68 (c 1.37, MeOH);

¹H NMR (400 MHz, CD₃OD) δ 7.10-7.10 (m, 5H), 3.60 (d, J=10.6 Hz, 1H),3.49-3.37 (m, 3H), 3.37-3.32 (m, 1H), 2.84 (dd, J=13.1, 5.4 Hz, 1H),2.69-2.53 (m, 2H), 2.42 (dd, J=13.0, 10.8 Hz, 1 H), 1.75-1.49 (m, 4H)ppm;

¹³C NMR (100 MHz, CD₃OD) δ 143.6 (^(Ar)Cq), 129.4 (^(Ar)CH), 129.3(^(Ar)CH), 126.7 (^(Ar)CH), 76.5 (CH), 75.1 (CH), 73.8 (CH), 65.6 (CH₂),60.3 (Cq), 45.8 (CH₂), 37.6 (CH₂), 27.5 (CH₂), 25.3 (CH₂) ppm;

HRMS (ESI⁺) Calc. C₁₅H₂₄NO₄ [M+H]+: m/z=282.16998; Found m/z=282.16968.

A.2/ Synthesis Method 2

The synthesis method used for obtaining compounds complying with thegeneral formula (I′a) below falls under the general synthesis scheme 2shown on FIG. 2 .

Compound of Formula (IId)

The compound of above formula (IId)(2R,3R,4R,5S)-2-(2-hydroxyethyl)-2-(hydroxymethyl)piperidine-3,4,5-triolis prepared in the following manner.

A mixture of nitrone (III) (566 mg, 1.05 mmol) and oftrimethylsilylacetylene alkyne (Vb: R⁸=SiMe₃, 2.2 mL, 15.75 mmol) wasstirred at ambient temperature for 21 hours, and then the excess alkynewas evaporated under reduced pressure. The raw isoxazoline B-2 thusobtained (667 mg, 1.05 mmol) was dissolved in anhydrous THF (20 mL) anda solution of TBAF (1M in THF, 1.05 mL, 1.05 mmol) was added at 0° C.The solution was stirred at 0° C. for 45 minutes, and then CH₂Cl₂ andwater were added. The aqueous phase was extracted three times withCH₂Cl₂. The organic phases were washed with brine, dried on MgSO₄, andthen the solvents were evaporated under reduced pressure. Purificationof the residue obtained by chromatography supplied bicyclic β-lactic C-2(440.6 mg, 74% in 2 steps). LiAlH₄ (9.6 mg, 0.25 mmol) was added at 0°C. to a solution of this β-lactam C-2 (71.3 mg, 0.13 mmol) in ether (1.5mL). The mixture was stirred at ambient temperature for 2 hours and thendiluted with CH₂Cl₂, aqueous NH₄Cl and a few drops of aqueous NaOH up tobasic pH. The aqueous phase was extracted (three times) with CH₂Cl₂. Theorganic phases were washed with brine, dried on MgSO₄, and the solventswere evaporated under reduced pressure to give piperidine D-2(translucent oil, 61.1 mg, 85%) after purification by chromatography.This compound (26.3 mg, 0.463 mmol) was debenzylated in accordance withthe general procedure B to give piperidine (IId) (9.3 mg, 97%). A paleyellow lacquer was obtained, with the following characteristics:

[α]²⁰ _(D)+8.2 (c 0.61, CH₃OH);

IR v 3287, 2920, 1644, 1431, 1081 cm⁻¹;

¹H NMR (500 MHz, CD₃OD) δ 1.86 (t, J=6.5 Hz, 2H), 2.65 (dd, J=11.2, 12.6Hz, 1H), 2.92 (dd, J=5.4, 13.1 Hz, 1H), 3.33-3.43 (m, 2H), 3.48 (d,J=9.1 Hz, 1H), 3.58 (d, J=10.8 Hz, 1H), 3.64-3.76 (m, 3H) ppm;

¹³C NMR (125 MHz, CD₃OD) δ 30.5 (CH₂), 45.8 (CH₂), 58.8 (CH₂), 60.9(C_(q)), 65.7 (CH₂), 73.5 (CH), 74.6 (CH), 76.3 (CH) ppm;

HRMS (ESI⁺) Calc. C₈H₁₈NO₅[M+H]⁺: m/z=208.1185; Found m/z=208.1184.

A.3/ Synthesis Method 3

The synthesis method used for obtaining compounds complying with thegeneral formula (I′d) below falls under the general synthesis scheme 3shown on FIG. 3 .

Compound of Formula (IIw)

The compound of above formula (IIw)(2S,3S,4R,5S)-3,4,5-tris(benzyloxy)-2-((benzyloxy)methyl)-2-(pyridin-2-ylsulfonyl)piperidin-1-olis prepared in the following manner. A solution of nitrone of formula(III) (196 mg; 0.366 mmol) and of 2-pyridyl-methylsulfone (Vla) (74.6mg; 0.475 mmol) in anhydrous THF (10 mL) under argon atmosphere wascooled to −78° C. 1M LiHMDS in THF (548 μL; 0.548 mmol) was addeddropwise and then the reaction mixture was stirred at this sametemperature until the reaction was complete. After the addition of waterand ethyl acetate, the aqueous phase was extracted (three times) withethyl acetate. The collected organic phases were washed with brine,dried on MgSO₄ and then concentrated at reduced pressure. Purificationof the residue obtained by chromatography supplied the compound offormula A-3a (R⁷=H) 115 mg; 55%). This compound was debenzylatedaccording to a variant of the general procedure B to give piperidine(IIw).

A.4/ Synthesis Methods 4

The synthesis methods used for obtaining compounds complying with thegeneral formula (I), in particular compounds complying with the generalformula (I′a), below fall under a general synthesis scheme 4 shown onFIG. 4 .

Compound of Formula (IIa)

The compound of above formula (IIa)((2R,3R,4R,5S)-2-ethyl-2-(hydroxymethyl)piperidine-3,4,5-triol) wasprepared in accordance with the general protocol B described for thesynthesis method 1, from piperidine D-4b (R¹⁷=vinyl, 74.0 mg, 0.137mmol), obtained as described in the publication by Boisson et al., 2015,Org. Lett. 17: 3662-3665, and was isolated with a yield of 95% (24.9mg).

A pale yellow lacquer is obtained, with the following characteristics:

[α]²⁰ _(D)+1.6 (c 1.22, CH₃OH);

IR v 3286, 2939, 1643, 1445, 1096 cm⁻¹;

¹H NMR (500 MHz, CD₃OD) δ 0.86 (t, J=7.6 Hz, 3H), 1.55-1.68 (m, 2H),2.51 (dd, J=10.8, 12.8 Hz, 1H), 2.89 (dd, J=5.4, 13.0 Hz, 1H), 3.34-3.40(m, 1H), 3.42 (d, J=10.7 Hz, 1H), 3.44-3.51 (m, 2H), 3.62 (d, J=10.7 Hz,1H) ppm; ¹³C NMR (125 MHz, CD₃OD) δ 7.0 (CH₃), 20.1 (CH₂), 45.7 (CH₂),60.5 (C_(q)), 65.0 (CH₂), 73.6 (CH), 75.1 (CH), 76.4 (CH) ppm;

HRMS (ESI⁺) Calc. C₈H₁₇NO₄[M+H]⁺: m/z=192.1236; Found m/z=192.1237.

Compound of Formula (IIb)

The compound of above formula (IIb)((2R,3R,4R,5S)-2-(hydroxymethyl)-2-propylpiperidine-3,4,5-triol) wasprepared in accordance with the general protocol B described for thesynthesis method 1, from piperidine D-4a (R¹⁷=allyl, 39.7 mg, 0.071mmol), obtained as described in the publication by Vieira Da Cruz etal., 2017, J. Org. Chem. 82: 9866-9872, and was isolated with a yield of79% (11.4 mg).

A colorless lacquer is obtained, with the following characteristics:

[α]²⁰ _(D)+5.4 (c 0.55, CH₃OH);

IR v 3291, 2932, 1625, 1454, 1090 cm⁻¹;

¹NMR (500 MHz, CD₃OD) δ 0.94 (t, J=7.2 Hz, 3H), 1.22-1.42 (m, 2H),1.49-1.57 (m, 2H), 2.53 (dd, J=10.8, 13.0 Hz, 1H), 2.89 (dd, J=5.5, 13.0Hz, 1H), 3.34-3.41 (m, 1H), 3.42 (d, J=10.7 Hz, 1H), 3.45-3.51 (m, 2H),3.64 (d, J=10.7 Hz, 1H) ppm;

¹³C NMR (125 MHz, CD₃OD) δ 15.3 (CH₃), 16.6 (CH₂), 30.4 (CH₂), 45.7(CH₂), 60.7 (CO, 65.3 (CH₂), 73.5 (CH), 74.9 (CH), 76.3 (CH) ppm;

HRMS (ESI⁺) Calc. C₉H₂₀NO₄ [M+H]⁺: m/z=206.1392; Found m/z=206.1396

Compound of Formula (IIe)

The compound of above formula (IIe)(2R,3R,4R,5S)-2-ethyl-2-(hydroxymethyl)-1-propylpiperidine-3,4,5-triolis prepared in the following manner.

The piperidine E-4b (R¹=allyl, R¹⁷=vinyl; 62 mg, 0.105 mmol), obtainedas described in the publication by Boisson et al., 2015, Org. Lett. 17:3662-3665, was dissolved in anhydrous acetonitrile (0.5 mL), treatedwith 2-nitrobenzenesulfonyl chloride (186 mg, 0.84 mmol) at 0° C., andthen with hydrazine monohydrate (0.08 mL, 1.68 mmol), added dropwise at0° C. This reaction mixture was maintained under stirring at ambienttemperature for 28 hours, and then water was added and the aqueous phasewas extracted (3 times) with dichloromethane. The collected organicphases were washed with brine, dried over MgSO₄ and concentrated underreduced pressure. After purification by chromatography, a mixture of theproducts of hydrogenation solely of the allyl group and of hydrogenationof the allyl and vinyl groups was isolated (58 mg, 94%, 3:7 mixture).This mixture was dissolved in methanol (1.5 mL), and then treated withPearlman's reagent (20% Pd(OH)₂/C, 16.8 mg, 0.119 mmol) and HCl (2 Msolution in ether, 0.2 mL, 0.4 mmol) under hydrogen atmosphere (1 atm)and under vigorous stirring for 40 hours. The mixture was filtered overCelite®, the Celite® was rinsed several times with methanol, then thefiltrate was concentrated under reduced pressure. The residue wassolubilized in water and purified on cation exchange resin (DOWEX50W-X8, form H⁺; elution by an aqueous solution of 1M NH₄OH) to providethe product (IIe) (11.9 mg, 49%). A beige solid is obtained, with thefollowing characteristics:

[α]²⁰ _(D)−40.7 (c 0.60, CH₃OH);

IR v 3363, 2962, 2932, 2874, 2826, 1653, 1464, 1379, 1097, 1048, 1016cm⁻¹ ¹H NMR (500 MHz, CD₃OD) δ□0.90 (t, J=7.5 Hz, 3H), 0.96 (t, J=7.5Hz, 3H), 1.39-1.50 (m, 1H), 1.51-1.60 (m, 1H), 1.61-1.75 (m, 2H),2.26-2.34 (m, 1H), 2.42-2.51 (m, 1H), 2.76-2.85 (m, 1H), 2.93-3.00 (m,1H), 3.40-3.52 (m, 3H), 3,65 (d, J=11.0 Hz, 1H), 3.79 (d, J=11.0 Hz, 1H)ppm;

¹³C NMR (125 MHz, CD₃OD) δ 9.6 (CH₃), 11.9 (CH₃), 19.2 (CH₂), 23.2(CH₂), 52.0 (CH₂), 52.2 (CH₂), 62.5 (CH₂), 71.5 (CH), 74.9 (CH), 76.4(CH) ppm;

HRMS (ESI⁺) Calc. C₁₁H₂₄NO₄ [M+H]⁺: m/z=234.1700; Found m/z=234.1696.

Compound of Formula (IIf)

The compound of formula (IIf) as above(1R,2R,3S,9aR)-9a-(hydroxymethyl)octahydro-1H-quinolizine-1,2,3-triol isprepared in the following manner.

Piperidine E-4a (R¹=R¹⁷=allyl; 35 mg, 0.06 mmol), obtained as describedin the publication by Vieira Da Cruz et al., 2017, J. Org. Chem. 82:9866-9872, was dissolved in anhydrous CH₂Cl₂ (3 mL). This solution wascarefully degassed, and then the Grubbs II catalyst (1.3 mg, 2.5 mol %)was added. The mixture was maintained under stirring at ambienttemperature for 20 hours, and then filtered over silica. The silica wasrinsed with ethyl acetate and methanol, and the solvents were evaporatedunder reduced pressure. After purification of the residue thus obtainedby chromatography, the product of cyclization by metathesis of F-4aolefins (32 mg, 95%) was isolated. The latter (34 mg, 0.06 mmol) wasdissolved in methanol (1 mL), and then treated with Pearlman's reagent(20% Pd(OH)₂/C, 14 mg, 0.10 mmol) and HCl (2M solution in ether, 0.045mL, 0.09 mmol) under hydrogen atmosphere (5 bar) and under vigorousstirring for 17 hours. The mixture was filtered over Celite®, theCelite®was rinsed several times with methanol, and then the filtrate wasconcentrated under reduced pressure. The residue was dissolved in waterand purified over cation exchange resin (DOWEX® 50W-X8, form H⁺; elutionby an aqueous solution of 1M NH₄OH) to provide the product (IIf) (9 mg,73%).

A colorless oil is obtained, with the following characteristics:

[α]²⁰ _(D)+16.6 (c 0,41, CH₃OH);

IR v 3336, 2942, 2869, 1053 cm⁻¹;

¹H NMR (500 MHz, CD₃OD) δ 1.28 (br d, J=11.6 Hz, 1H), 1.37-1.44 (m, 1H),1.62-1.76 (m, 3H), 1.81-1.94 (m, 1H), 2.66 (dd, J=3.0, 14.0 Hz, 1H),2.72 (dd, J=4.9, 11.3 Hz, 1H), 3.12 (t, J=11.0 Hz, 1H), 3.20 (pstd,J=3.0, 14.0 Hz, 1H), 3.38 (pst, J=9.3 Hz, 1H), 3.45-3.52 (m, 2H), 3.68(d, J=11.1 Hz, 1H), 3.95 (d, J=11.1 Hz, 1H) ppm;

¹³C NMR (125 MHz, CD₃OD) δ 18.7 (CH₂), 19.2 (CH₂), 20.7 (CH₂), 48.5(CH₂), 53.3 (CH₂), 60.7 (CH₂), 62.0 (C_(q)), _(71.4) (CH), 74.1 (CH),75.9 (CH) ppm; HRMS (ESI⁺) Calc. C₁₀H₂₀NO₄ [M+H]⁺: m/z=218.1392; Foundm/z=218.1396.

Compound of Formula (IIg)

The compound of formula (IIg) as above (6S, 7R, 8R,8aR)-8a-(hydroxymethyl)-octahydroindolizine-6,7,8-triol is prepared inthe following manner.

Piperidine E-4b (R¹=allyl, R¹⁷=vinyl; 74 mg, 0.125 mmol), obtained asdescribed in the publication by Boisson et al., 2015, Org. Lett. 17:3662-3665, was dissolved in anhydrous CH₂Cl₂ (6.3 mL). This solution wascarefully degassed, and then the Grubbs II catalyst (5.3 mg, 0.006 mmol)was added and the mixture was heated at 40° C. for 3 hours, understirring. After cooling to ambient temperature, the reaction mixture wasfiltered over silica, the silica was rinsed with ether, and the solventswere evaporated under reduced pressure. After purification of theresidue thus obtained by chromatography, the product of cyclization bymetathesis of olefins F-4b (65 mg, 93%) was isolated. The latter (50 mg,0.089 mmol) was dissolved in methanol (1.4 mL), then treated withPearlman's reagent (20% Pd(OH)₂/C, 17.9 mg, 0.025 mmol) and HCl (2Msolution in ether, 0.066 mL, 0.133 mmol) under hydrogen atmosphere (5bar) and under vigorous stirring for 17 h. The mixture was filtered overCelite®, the Celite® was rinsed several times with methanol, and thenthe filtrate was concentrated under reduced pressure. The residue wasdissolved in water and purified over cation exchange resin (DOWEX50W-X8, form H⁺; elution by an aqueous solution of 1M NH₄OH) to providethe product (IIg) (16 mg, 89%).

A beige solid is obtained, with the following characteristics:

[α]²⁰ _(D)+27.9 (c 0.41, CH₃OH);

IR v 3330, 2924, 1652, 1031 cm⁻¹;

¹H NMR (500 MHz, CD₃OD) δ 1.46-1.53 (m, 1H), 1.67-1.76 (m, 1H),1.88-1.96 (m, 1H), 1.98-2.08 (m, 1H), 2.46 (pst, J=11.0 Hz, 1H),2.80-2.89 (m, 2H), 3.09-3.18 (m, 1H), 3.33-3.41 (m, 2H), 3.43-3.49 (m,1H), 3.53 (d, J=11.5 Hz, 1H), 3.76 (d, J=9.5 Hz, 1H) ppm;

¹³C NMR (125 MHz, CD₃OD) δ 21.0 (CH₂), 26.1 (CH₂), 53.8 (CH₂), 55.9(CH₂), 63.6 (CH₂), 71.0 (CH), 73.0 (CH), 73.2 (Cq), 76.5 (CH) ppm;

HRMS (ESI⁺) Calc. C₉H₁₈NO₄ [M+H]⁺: m/z=204.1236; Found m/z=204.1234.

A.5/ Synthesis Methods 5

The synthesis method used for obtaining the compound complying with thegeneral formula (I′b) as above falls under a general synthesis scheme 5shown on FIG. 5 .

Compound (IIh)

The compound of above formula (IIh)((3S,4R,5R,6R)-6-(hydroxymethyl)-1-azabicyclo[4.2.0]octane-3,4,5-triol)is prepared in the following manner.

[Rh(COD)_(2])BF₄ (2.5 mg, 0.006 mmol), 1,3-bis(diphenylphosphino)propane(2.7 mg, 0.006 mmol) and PhSiH₃ (25 μL, 0.20 mmol) were added to asolution of β-lactam C-5 (corresponding to the compound C-2 obtained asintermediate in synthesis method 2, as described in the protocol forpreparing the compound (IId) above) (57.1 mg, 0.10 mmol) in distilledTHF. The solution was stirred at 50° C. for 4 hours. After cooling, thereaction mixture was diluted with EtOAc and aqueous NaOH (1 M). Theaqueous phase was extracted (three times) with EtOAc. The organic phaseswere washed with brine, dried over MgSO₄, and the solvents wereevaporated under reduced pressure to give conidine G-5 (33.2 mg, 60%)after purification by chromatography. This compound (20.0 mg, 0.04 mmol)was debenzylated in accordance with the general procedure B to give thecompound (IIh) (6.3 mg, 93%).

A pale yellow oil is obtained, with the following characteristics:

[α]²⁰ _(D)−5.17 (c 0.58, CH₃OH);

IR v 3234, 2917, 1429, 1030 cm⁻¹;

¹H NMR (500 MHz, CD₃OD) δ 2.18-2.26 (m, 1H), 2.55-2.63 (m, 1H), 2.89(dd, J=5.9, 13.3 Hz, 1H), 3.21 (dd, J=5.1, 13.3 Hz, 1H), 3.62 (d, J=11.7Hz, 1H), 3.69-3.80 (m, 5H), 3.99 (pst, J=6.5 Hz, 1H) ppm;

¹³C NMR (125 MHz, CD₃OD) δ 21.3 (CH₂), 51.4 (CH₂), 52.9 (CH₂), 65.5(CH₂), 71.2 (CH), 72.7 (CH), 73.2 (C_(q)), 76.8 (CH) ppm;

HRMS (ESI⁺) Calc. C₈H₁₆NO₄ [M+H]⁺m/z=190.1074; Found m/z=190.1074.

General Protocol C—reducing alkylation of β-lactam C-5 leading toconidines of general formula (I′b)

A solution of β-lactam C-5 (1 equiv.) and of Vaska's catalyst (4% mol)in anhydrous dichloromethane under argon atmosphere is added totetramethyldisiloxane (TMDS, 2 equiv.) at ambient temperature. Themixture is stirred for 45 minutes and then cooled to −78° C. Grignardreagent (2 equiv.) is added dropwise and then the mixture is stirred for7-10 minutes at this same temperature before increasing to ambienttemperature. It is next stirred for 21 hours. A saturated aqueoussolution of NH₄Cl is added and then the resulting mixture is dilutedwith CH₂Cl₂. The organic phase is separated and the aqueous phase isextracted twice with CH₂Cl₂. The organic phases are washed with brine,dried over MgSO₄ and evaporated under reduced pressure. The conidines offormula (I′b) thus formed are purified by chromatography over silica gelbefore being reduced and debenzylated in accordance with the generalprotocol B above.

Compound (IIz2)

The compound of above formula (1Iz2)((3S,4R,5R,6R,8R)-8-benzyl-6-(hydroxymethyl)-1-azabicyclo[4.2.0]octane-3,4,5-triol:20.3 mg; 65% for 2 steps) was prepared in accordance with the generalprocedures C and B, from β-lactam C-5 (70.1 mg; 0.124 mmol) and 2Mbenzylmagnesium chloride in THF (R¹⁴=Bn; 36.3 μL; 0.248 mmol).

A translucent lacquer is obtained, with the following characteristics:

¹H NMR (500 MHz, CD₃OD) δ 7.39-7.20 (m, 5H), 4.45-4.34 (m, 1H), 3.95 (t,J=5.7 Hz, 1H), 3.80-3.74 (m, 2H), 3.70 (d, J=5.6 Hz, 1H), 3.56 (d,J=12.1 Hz, 1H), 3.21-3.12 (m, 2H), 3.00 (dd, J=13.6, 8.4 Hz, 1H), 2.94(dd, J=13.1, 6.5 Hz, 1H), 2.60 (dd, J=11.9, 9.0 Hz, 1H), 2.32-2.20 (m,1H) ppm;

¹³C NMR (125 MHz, CD₃OD) δ 137.1 (^(Ar)Cq), 130.1 (^(Ar)CH), 129.7(^(Ar)CH), 128.0 (^(Ar)CH), 76.5 (CH), 71.5 (CH), 71.1 (CH), 65.7 (CH),64.1 (CH₂), 51.4 (CH₂), 41.0 (CH₂), 27.3 (CH₂) ppm;

HRMS (ESI⁺) Calc. C15H22NO₄ [M+H]⁺: m/z=280.15433; Found m/z=280.15437.

Compound (IIz3)

The compound of above formula (IIz3)((3S,4R,5R,6R,8R)-6-(hydroxymethyl)-8-methyl-1-azabicyclo[4.2.0]octane-3,4,5-triol:8.5 mg; 46% for 2 steps) was prepared in accordance with the generalprocedures C and B, from β-lactam C-5 (192.6 mg; 0.342 mmol) and 3Mmethylmagnesium chloride in THF (R¹⁴⁼Me; 228 μL; 0.683 mmol).

A yellowish solid is obtained, with the following characteristics:

[60 ]²⁰ _(D)−22.9 (c 1.07, MeOH);

¹H NMR (500 MHz, CD₃OD) δ 3.99 (t, J=6.7 Hz, 1H), 3.85-3.75 (m, 1H),3.75-3.69 (m, 1H), 3.67 (d, J=7.6 Hz, 1H), 3.54 (d, J=11.2 Hz, 1H), 3.47(d, J=11.2 Hz, 1H), 3.10 (dd, J=13.9, 5.5 Hz, 1H), 2.71 (dd, J=13.8, 4.0Hz, 1H), 2.58 (dd, J=11.5, 8.9 Hz, 1H), 1.64 (dd, J=10.9, 8.0 Hz, 1H),1.21 (d, J=6.1 Hz, 3H) ppm;

¹³C NMR (100 MHz, CD₃OD) δ 77.2 (CH), 74.7 (CH), 71.7 (CH), 68.3 (Cq),67.4 (CH₂), 58.4 (CH), 52.4 (CH₂), 29.1 (CH₂), 22.0 (CH₃) ppm; HRMS(ESI⁺) Calc. C₉H₁₈NO₄ [M+H]⁺: m/z=204.12303; Found m/z=204.12232.

Compound (IIz4)

The compound of above formula (IIz4)((3S,4R,5R,6R,8S)-8-cyclopentyl-6-(hydroxymethyl)-1-azabicyclo[4.2.0]octane-3,4,5-triol:14.6 mg; 62% for 2 steps) was prepared in accordance with the generalprocedures C and B, from β-lactam C-5 (70.0 mg; 0.124 mmol) and 2Mcyclopentylmagnesium chloride in ether (R¹⁴=cPent; 36.4 μL; 0.248 mmol).

A yellowish solid is obtained, with the following characteristics:

¹H NMR (500 MHz, CD₃OD) δ 3.98 (t, J=7.0 Hz, 1H), 3.76-3.63 (m, 2H),3.58-3.36 (m, 3H), 3.10 (dd, J=14.5, 5.0 Hz, 1H), 2.76 (dd, J=14.5, 4.0Hz, 1H), 2.50 (t, J=11.8 Hz, 1H), 2.06-1.95 (m, 1H), 1.89-1.76 (m, 1H),1.74-1.47 (m, 6H), 1.36-1.22 (m, 1H), 1.15-1.00 (m, 1H) ppm;

¹³C NMR (125 MHz, CD₃OD) δ 77.7 (CH), 75.0 (CH), 71.9 (CH), 67.5 (CH₂),67.2 (CH), 66.3 (Cq), 54.2 (CH₂), 48.9 (CH), 31.0 (CH₂), 29.1 (CH₂),27.0 (CH₂), 26.4 (CH₂), 25.9 (CH₂) ppm;

HRMS (ESI⁺) Calc. C₁₃H₂₄NO₄ [M+H]⁺: m/z=258.16998; Found m/z=258.16987.

Compound (IIz5)

The compound of above formula (IIz5)((3S,4R,5R,6R,8R)-6-(hydroxymethyl)-8-pentyl-1-azabicyclo[4.2.0]octane-3,4,5-triol:19.1 mg; 45% for 2 steps) was prepared in accordance with the generalprocedures C and B, from β-lactam C-5 (70.0 mg; 0.124 mmol) and 2Mpentylmagnesium chloride in THF (R¹⁴=n-Pent; 33.6 μL; 0.248 mmol).

A yellow solid is obtained, with the following characteristics:

[α]²⁰ _(D)−31.1 (c 0.46, MeOH);

1H NMR (500 MHz, CD₃OD) δ 3.99 (t, J=7.0 Hz, 1H), 3.74-3.64 (m, 2H),3.64-3.55 (m, 1H), 3.51 (d, J=11.1 Hz, 1H), 3.46 (d, J=11.1 Hz, 1H),3.09 (dd, J=13.7, 5.4 Hz, 1H), 2.70 (dd, J=13.7, 4.0 Hz, 1H), 2.52 (dd,J=11.4, 8.9 Hz, 1H), 1.68-1.53 (m, 2H), 1.51-1.39 (m, 1H), 1.39-1.21 (m,6H), 0.90 (t, J=6.7 Hz, 3H) ppm;

¹³C NMR (100 MHz, CD₃OD) δ 77.5 (CH), 75.2 (CH), 71.9 (CH), 67.8 (CH₂),66.4 (Cq), 62.4 (CH), 53.8 (CH₂), 38.8 (CH₂), 33.0 (CH₂), 27.9 (CH₂),26.5 (CH₂), 23.7 (CH₂), 14.3 (CH₃) ppm;

HRMS (ESI⁺) Calc. C₁₃H₂₆NO₄ [M+H]⁺: m/z=260.18563; Found m/z=260.18561.

A.6/ Synthesis Method 7

The synthesis method used for obtaining the compounds complying with thegeneral formula (I′c) below falls under the general synthesis scheme 7shown on FIG. 7 .

Compound (IIk)

The compound of formula (IIk) as above((3S,4R,5R,6R,7S)-6,7-bis(hydroxymethyl)-1-azabicyclo[4.1.0]heptane-3,4,5-triol)is obtained in the following manner.

A mixture of nitrone (III) (P=Bn; 193 mg, 0.360 mmol) and of alkyne Vc(R⁸=NBnTs; 308 mg, 1.079 mmol) in solution in CH₂Cl₂ (0.4 mL) wasstirred at ambient temperature for 3 days, and then the reaction mixturewas concentrated under reduced pressure. The residue (raw cycloadductB-7c) was dissolved in ethanol (0.1M), transferred into a sealed tube,and heated at 110° C. (IR probe) under microwave irradiation for 15minutes. After concentration under reduced pressure, the residue waspurified by chromatography to give acylaziridine H-7c (P=Bn, R⁸=NBnTs;238 mg, 80% on 2 steps). A fraction of this compound (58 mg, 0.070 mmol)was dissolved in THF (1 mL), and then LiAlH4 (6 mg, 0.157 mmol) wasadded at 0° C. The mixture was stirred for 1.5 hours at ambienttemperature. After adding water (0.1 mL) and a 10% aqueous solution ofNaOH (0.1 mL), the reaction mixture was stirred at ambient temperaturefor 2 hours and then filtered over Celite®. The filtrate, concentratedunder reduced pressure, was purified by chromatography to isolate theaziridine-alcohol J-7c (P=Bn, R¹⁶=H; 34.2 mg, 86%). A solution of thisaziridine-alcohol J-7c (28 mg, 0.067 mmol) in THF (2 mL) was added to asolution of lithium (54 mg, 7.78 mmol) in liquid ammonia (10 mL) at −78°C. The mixture was stirred for 45 minutes at -78° C., and then Milli-Qwater (0.5 mL) and MeOH (2 mL) were added. After returning the solutionto ambient temperature, the solvents were evaporated under reducedpressure. The residue was dissolved in Milli-Q water and neutralizedwith Amberlite® IR-120 (22.8 g) previously treated with 1M HCl (15 mL).The resin was introduced into a column, washed with water, and then thecompound (IIk) was eluted with a 1M solution of aqueous NH₄OH. Thesolution obtained after evaporation of the solvents under reducedpressure was purified by chromatography to give the pure iminosugar(IIk) (R¹⁶=H; 7 mg, 60%).

A white solid is obtained, with the following characteristics:

[α]²⁰ _(D)=+2.90 (c 0.34, CH₃OH);

IR v 3409, 3010, 2926, 1084, 1032 cm⁻¹;

¹H NMR (500 MHz, CD₃OD) δ 4.16 (d, J=7.9 Hz, 1H), 3.79 (d, J=11.6 Hz,1H), 3.60-3.50 (m, 3H), 3.47-3.40 (m, 1H), 3.33-3.25 (m, 2H), 2.55 (dd,J=10.6, 12.4 Hz, 1H), 2.19 (dd, J=6.8, 5.3 Hz, 1H) ppm;

¹³C NMR (125 MHz, CD₃OD) 576.0 (CH), 73.2 (CH), 70.6 (CH), 63.2 (CH₂),62.0 (CH₂), 57.0 (CH₂), 51.9 (C_(q)), 51.6 (CH) ppm;

HRMS (ESI⁺) Calc. C₈H₁₆NO₅ [M+H]⁺ m/z=206.1028; Found m/z=206.1028.

Compound (IIj)

The compound of above formula (IIj)((3S,4R,5R,6R,7S)-7-((S)-1,2-dihydroxyethyl)-6-(hydroxymethyl)-1-azabicyclo[4.1.0]heptane-3,4,5-triol)is obtained as follows.

Acylaziridine H-7d (P=Bn, R⁸=CH₂OAc; 33 mg, 0.052 mmol), obtained asdescribed in the publication by Tangara et al., 2017, Org. Lett. 19:4842-4845, was dissolved in THF (1 mL), and then LiAlH4 (38 mg, 0.165mmol) was added at 0° C. and the mixture was stirred for 1 hour atambient temperature. After adding water (0.1 mL) and a 10% aqueoussolution of NaOH (0.1 mL), the reaction mixture was stirred at ambienttemperature for 2 hours and then filtered over Celite®. The filtrate,concentrated under reduced pressure, was purified by chromatography toisolate a translucent oil J-7d (R¹⁶=CH₂OH; 26 mg, 83%). A solution ofthis aziridine-alcohol J-7d (40 mg, 0.067 mmol) in THF (2 mL) was addedto a solution of lithium (25 mg, 3.571 mmol) in liquid ammonia (10 mL)at −78° C. The mixture was stirred for 45 minutes at −78° C. and thenMilli-Q water (0.5 mL) and MeOH (2 mL) were added. After returning thesolution to ambient temperature, these solvents were evaporated underreduced pressure. The residue was dissolved in Milli-Q water andneutralized with Amberlite® IR-120 (8.5 g) previously treated with 1MHCl (5 mL). The resin was introduced into a column, washed with water,and then the compound (IIj) was eluted with a 1M solution of aqueousNH₄OH. The solid obtained after evaporation of the solvents underreduced pressure was purified by chromatography to give the pureiminosugar (IIj) (R¹⁶=CH₂OH; 10.1 mg, 64%).

A white solid is obtained, with the following characteristics:

[α]²⁰ _(D)=+5.90 (c 0.34, CH₃OH);

IR: v 3249, 2939, 2885, 1748, 1656, 1404, 1031, 995 cm⁻¹;

¹H NMR (500 MHz, CD₃OD) δ 4.16 (d, J=8.0 Hz, 1H), 3.91 (d, J=11.6 Hz,1H), 3.71 (dd, J=3.5, 11.4 Hz, 1H), 3.61 (dd, J=5.8, 11.4 Hz, 1H),3.54-3.48 (m, 1H), 3.48-3.41 (m, 1H), 3.39 (d, J=11.6 Hz, 1H), 3.30-3.25(m, 2H), 2.52 (dd, J=10.2, 12.2 Hz, 1H), 2.10 (d, J=8.7 Hz, 1H) ppm;

¹³C NMR (125 MHz, CD₃OD) δ 75.9 (CH), 73.1 (CH), 72.4 (CH), 70.7 (CH),66.1 (CH₂), 63.8 (CH₂), 56.5 (CH₂), 52.0 (C_(q)), 51.2 (CH) ppm;

HRMS (ESI⁺) Calc. C₉H₁₈NO₆ [M+H]⁺m/z=236.1129; Found m/z=236.1124.

Compound (IIm)

The compound of above formula (IIm)(3S,4R,5R,6R,7S)-7-((S)-hydroxy(phenyl)methyl)-6-(hydroxymethyl)-1-azabicyclo[4.1.0]heptane-3,4,5-triolis obtained as follows.

The cycloadducts B-7e (P=Ac, R⁸=Ph; 15.2 mg, 0.030 mmol, 4:1 mixture ofdiastereoisomers), obtained as described in the publication by Tangaraet al., 2018, New J. Chem. 42: 16735-16743, were dissolved indichloroethane (0.1M solution) in a sealed tube. The solution was heatedat 110° C. (IR probe) under irradiation by microwave for 45 minutes(30+15). After evaporation of the solvent under reduced pressure,purification of the residue by chromatography made it possible toisolate the acylaziridines H-7e (P=Ac, R⁸=Ph; 12 mg, 79%) in the form ofa 9:1 mixture of two diastereoisomers. These acylaziridines (30 mg,0.067 mmol) were dissolved in THF (1.2 mL), the solution was cooled to0° C. and then LiAlH4 (5.6 mg, 0.147 mmol) was added. The reactionmixture was stirred at ambient temperature for 1.5 hours, and then water(0.1 mL) and a 10% aqueous solution of NaOH (0.1 mL) were added thereto.After stirring at ambient temperature for 1.5 hours, this mixture wasfiltered over Celite®, the filtrate being concentrated under reducedpressure, and the residue was purified by chromatography to provide theaziridinyl iminosugar (IIm) (R¹⁶=Ph; 15 mg, 82%) in the form of a singlediastereoisomer.

A colorless oil is obtained, with the following characteristics:

[α]²⁰ _(D)−4.1 (c 1.58, CH₃OH);

IR v 3296, 2931, 1557, 1409, 1053, 697 cm⁻¹;

¹H NMR (500 MHz, CD₃OD) δ 7.49-7.44 (m, 2H), 7.40-7.35 (m, 2H),7.31-7.25 (m, 1H), 4.29 (d, J=8.7 Hz, 1H), 4.18 (d, J=7.9 Hz, 1H), 4.01(d, J=11.6 Hz, 1H), 3.56 (d, J=11.6 Hz, 1H), 3.48-3.37 (m, 2H), 3.26(dd, J=9.1, 8.0 Hz, 1H), 2.26-2.18 (m, 2H) ppm;

¹³C NMR (125 MHz, CD₃OD) δ 144.6 (^(Ar)C_(q)), 129.5 (^(Ar)CH), 128.6(^(Ar)CH), 127.1 (^(Ar)CH), 75.8 (CH), 73.8 (CH), 73.1 (CH), 70.7 (CH),63.6 (CH₂), 56.4 (CH₂), 56.0 (CH), 52.8 (C_(q))

ppm;

HRMS (ESI⁺) Calc. C₁₄H₂₀NO₅ [M+H]⁺: m/z=282.1341; Found m/z=282.1346.

Compound (IIn)

The compound of above formula (IIn)(3S,4R,5R,6R,7S)-7-((R)-cyclohexyl(hydroxy)methyl)-6-(hydroxymethyl)-1-azabicyclo[4.1.0]heptane-3,4,5-triolis obtained as follows.

Acylaziridine H-7f (P=Bn, R⁸=c-Hex; 77 mg, 0.119 mmol), obtained asdescribed in the publication by Tangara et al., 2017, Org. Lett. 19:4842-4845, was dissolved in ethanol (1.4 mL), cooled to 0° C., and thenNaBH₄ (13 mg, 0.342 mmol) was added. The mixture was stirred at the sametemperature for 3.3 hours, and then water, a 10% aqueous solution ofNaOH and CH₂Cl₂ were added. The aqueous phase was extracted (3 times) byCH₂Cl₂, the organic phases were collected, dried on MgSO₄ andconcentrated under reduced pressure. The residue thus obtained wasfiltered on silica to isolate the aziridine-alcohol J-7f (R¹⁶=c-Hex; 72mg, 94%) in the form of an oil. A solution of this aziridine-alcoholJ-7f (42 mg, 0.064 mmol) in THF (4 mL) was added to a solution oflithium (12 mg, 2.0 mmol) in liquid ammonia (10 mL) at −78° C. Thereaction mixture was stirred for 45 minutes at −78° C., and then Milli-Qwater (0.5 mL) and MeOH (2 mL) were added. After returning the solutionto ambient temperature, the solvents were evaporated under reducedpressure. The residue was dissolved in Milli-Q water and neutralizedwith Amberlite® IR-120 (3.5 g) previously treated with 1M HCl (2 mL).The resin was introduced into a column, washed with water, and then thecompound (IIn) was eluted with a 1M solution of aqueous NH₄OH. The solidobtained after evaporation of the solvents under reduced pressure waspurified by chromatography to give the pure iminosugar (IIn) (R¹⁶=c-Hex;13 mg, 72%).

A white solid is obtained, with the following characteristics:

[α]²⁰ _(D)+2.8 (c 0.80, CH₃OH);

IR v 3335, 2916, 2846, 1451, 1087, 1054, 1008, 660 cm⁻¹;

¹H NMR (500 MHz, CD₃OD) δ 4.17 (d, J=7.8 Hz, 1H), 3.88 (d, J=11.7 Hz,1H), 3.50-3.44 (m, 2H), 3.42 (d, J=11.7 Hz, 1H), 3.33-3.29 (m, 1H), 2.95(dd, J=8.6, 6.6 Hz, 1H), 2.51 (dd, J=11.8, 9.0 Hz, 1H), 2.08 (d, J=8.7Hz, 1H), 1.99-1.66 (m, 5H), 1.53-1.45 (m, 1H), 1.36-1.03 (m, 5H) ppm;

¹³C NMR(125 MHz, CD₃OD) δ 76.3 (CH), 76.0 (CH), 73.3 (CH), 70.8 (CH),64.1 (CH₂), 56.0 (CH₂), 52.9 (CH), 51.1 (C_(q)), 45.3 (CH), 30.1 (CH₂),29.7 (CH₂), 27.7 (CH₂), 27.4 (CH₂), 27.2 (CH₂) ppm;

HRMS (ESI⁺) Calc. C₁₄H₂₆NO₅ [M+H]⁺: m/z=288.1811; Found m/z=288.1810.

A.7/ Synthesis Method 8

A synthesis method used for obtaining a compound complying with thegeneral formula (I′e) below falls under the general synthesis scheme 8shown on FIG. 8 .

Compound (IIw1)

The compound of above formula (IIw1)((2R,3R,4R,5S)-2-(hydroxymethyl)-2-(1H-1,2,3-triazol-4yl)piperidine-3,4,5-triolis prepared in the following manner. A solution of hydroxylamine offormula A-1a (240.0 mg; 0.377 mmol) and of zinc powder (247.0 mg; 3.77mmol) in a 4:1 mixture EtOH/AcOH (5 mL) was stirred at 65° C. underultrasound until the reaction was complete. The reaction mixture isfiltered over Celite and then evaporated under reduced pressure. The rawproduct is redissolved in CH₂Cl₂ and then treated with aqueous 1M NaOH.The aqueous phase was extracted (three times) with CH₂Cl₂. The organicphases were washed with brine, dried over MgSO₄ and then evaporatedunder reduced pressure. Purification of the residue obtained bychromatography provided the corresponding piperidine D-8 (178.0 mg;76%). A mixture of this piperidine D-8 (176.0 mg; 0.284 mmol), of benzylchloroformiate (121 μL; 0.852 mmol) and of K₂CO₃ (157.0 mg; 1.14 mmol)in anhydrous THF (1.7 mL) was stirred at ambient temperature until thereaction was complete. Methanol (2 mL) was added and then the reactionmixture was stirred at ambient temperature until the reaction wascomplete. Purification of the residue obtained by chromatographyprovided the compound of formula K-8 (164.0 mg; 78% over 2 steps).Copper iodide (3.5 mg; 0.018 mmol) and DIPEA (108 μL; 0.618 mmol) wereadded to a solution of this same compound K-8 (46.8 mg; 0.062 mmol) andof benzyl azide (247 μL; 0.124 mmol) in DMF (1.5 mL) under inertatmosphere. The reaction mixture was stirred at ambient temperatureuntil the reaction was complete. The raw product was diluted in ethylacetate and washed several times with brine. The organic phase was driedover MgSO₄ and evaporated at reduced pressure. Purification of theresidue obtained by chromatography provided the compound of formula L-8(38.2 mg; 76%). This compound (32.1 mg; 0.039 mmol) was debenzylated inaccordance with the general procedure B to give piperidine (IIw1) (11.0mg; 100%).

A colorless lacquer is obtained, with the following characteristics:

[α]²⁰ _(D)−17.2 (c 1.09, CH₃OH);

1H NMR (500 MHz, CD₃OD) δ 7.90 (s, 1H), 3.80 (d, J=10.9 Hz, 1H), 3.69(d, J=9.7 Hz, 1H), 3.59 (d, J=11.1 Hz, 1H), 3.52-3.45 (m, 1H), 3.27 (t,J=9.3 Hz, 1H), 2.99 (dd, J=12.6, 5.5 Hz, 1H), 2.54 (dd, J=12.3, 11.2 Hz,1H) ppm;

¹³C NMR (125 MHz, CD₃OD) δ 144.5 (Cq), 131.0 (CH), 76.9 (CH), 74.5 (CH),73.0 (CH), 68.1 (CH₂), 62.5 (Cq), 47.2 (CH₂) ppm;

HRMS (ESI⁺) Calc. C₈H₁₅N₄O₄ [M+H]⁺: m/z=231.10878; Found m/z=231.10861.

B/ Biological Evaluations

The following various biological activity tests are implemented on thecompounds (IIa) to (IIn) described above.

B.1/ Inhibition of rhGAA Determined by Fluopol-ABPP

The inhibiting activity on recombinant human acid α-glucosidase (rhGAA)of the compounds is implemented using the Fluopol-ABPP method(Fluorescence Polarization Activity Based Protein Profiling) describedin the publication of Lahav et al., 2017, J. Am. Chem. Soc. 139:14192-14197. This technique, based on the competition between aninhibitor and a fluorescent probe capable of binding covalently to theactive site of an enzyme, makes it possible to measure the affinity ofthis inhibitor for the active site of the rhGAA enzyme used for theseexperiments by the laboratory of Professors Herman S. Overkleeft andJohanes M. F. G. Aerts, Leiden Institute of Chemistry, Leiden University(NL), is the enzyme marketed under the name Myozyme®. The medianinhibiting concentrations (IC₅₀) are determined in the Mcllvaine buffer(citrate-phosphate) 150 mM at pH 5.0, in the presence of 0.1% bovinegamma-globulin (p/v) and 0.5 mg/mL of Chaps detergent (Sigma) in 96-wellplates (Griener). The rhGAA enzyme (10 μg/mL) is pre-incubated withsolutions of inhibitor (containing 2.5% DMSO that was used to preparethe mother solutions of the compounds) at various concentrations [I] inthe buffer, for 45 minutes at 37° C. The tetraaminomethylrhodamine(TAMRA) fluorescent probe in solution (25 nM) in the buffer is nextadded to the mixture. After 4 hours, the samples are irradiated with apolarized light (λ=530 nm) and the fluorescence emitted (λ=580 nm) ismeasured by means of an Infinite® M1000Pro (Tecan) spectrofluorimeter.For each concentration of inhibitor, the percentage of inhibition of theenzyme is determined by the formula:

%Inhibition=[F _(measured) −F _(control1))/F _(contro2))×100

where F_(measured) corresponds to the fluorescence measured in thepresence of the iminosugars; F_(control1) corresponds to thefluorescence measured in the presence of a powerful inhibitor of humanacid α-glucosidase acid serving as a positive control (100% inhibition),CF 022((1S,2R,3S,4R,5R,6R)-2,3,4-trihydroxy-5-(hydroxymethyl)-7-(8-azidooctyl)-7-aza-bicyclo[4.1.0]heptane),and F_(control2) represents the fluorescence of the probe measured inthe absence of the inhibitor (0% inhibition).

The IC₅₀ values are calculated by a non-linear regression of the %inhibition as a function of the concentration [I] by means of theGraphPad Prism 6.0 software. The results are a mean of three identicalexperiments (triplicates).

B.2/ Inhibition of rhGAA Determined by Measuring the Residual Activityin the Presence of an Inhibitor in Vitro

In a complementary way, the activity of inhibition of recombinant humanacid α-glucosidase (rhGAA) of the compounds was evaluated by the team ofProfessor Marco Moracci, Department of Biology, University of NaplesFederico II (IT), using the method described in the publication of Portoet al., 2012, Molecular Therapy 20: 2201-2211. The rhGAA enzyme soldunder the name Myozyme® used comes from residues of perfusions of therecombinant enzyme used for treating, by enzyme therapy, the patientswith Pompe disease in the Department of Translational Medical Sciences,University of Naples Federico II (IT). The compounds are solubilized atvarious concentrations in a 100 mM sodium acetate buffer, pH 4.0, aswell as the 4-nitrophenyl-α-D-glucopyranoside substrate (20 mM). After 2minutes of equilibration of the temperature at 37° C., the rhGAA enzymein solution in the same buffer is added (total volume: 200 μL). After 2minutes of reaction at 37° C., a 1M solution of sodium carbonate (800μL), pH 11.0, is added and the mixture is cooled in ice. The absorbanceof the solution is measured at 420 nm at ambient temperature. Thespontaneous hydrolysis of the substrate is subtracted by measuring theabsorbance of controls (blanks) without enzyme. The results given arethe mean of at least two identical experiments. The data are processedand analyzed using Prism 5.0 software (GraphPad).

B.3/ Determination of the Thermal Stabilization of rhGAA

The stabilization of rhGAA in the presence of the compounds isdetermined in accordance with the method described in the publication ofNiesen et al., 2007, Nat. Protoc. 2: 2212-2221. The rhGAA enzyme (2.5μg, 0.1 mg/mL) is incubated in the absence and in the presence of eachcompound (at a concentration [I]=100 μM), of SYPRO® orange dye (LifeTechnologies), and of sodium phosphate buffer (25 mM) and of NaCI (150mM), pH 7.4 or of sodium acetate buffer (25 mmol) and of NaCl (150 mM),pH 4.0. The thermal stability of the enzyme in these various conditionsis evaluated by DSF (differential scanning fluorimetry) by varying thetemperature by 1° C./min over an interval of 25 to 95° C., and measuringthe fluorescence of the SYPRO® orange dye every minute by means of aReal-Time Cycler spectrofluorimeter (Biorad). The relative fluorescenceis determined by comparing each fluorescence value measured with that ofthe maximum fluorescence value of the SYPRO® orange dye for each scan.The results are a mean of three identical experiments (triplicates).

B.4/ Evaluation of the Inhibition of Other Enzymes of Human Origin

The selectivity of the compounds was evaluated in the laboratory ofProfessors Herman S. Overkleeft and Johanes M. F. G. Aerts, LeidenInstitute of Chemistry, Leiden University (NL). The enzymes used fordetermining the selectivity of inhibition of the compounds with respectto various human enzymes are the α-glucosidase II of the endoplasmicreticulum (GANAB), recombinant human lysosomal β-glucocerebrosidase(GBA1), human non-lysosomal β-glucosylceramidase (GBA2) andβ-glucosylceramide synthase (GCS). The inhibiting activity of thecompounds on these various enzymes is determined as described in thepublication by Artola et al., 2017, ACS Cent. Sci. 3: 784-793. Theenzyme GBA1 sold under the name Cerezyme® and the enzyme rhGAA soldunder the name Myozyme® are used. The human GANAB enzyme used for thisstudy is that of fibroblasts of patients suffering from Pompe diseasediagnosed as lacking active GAA and voluntary donors. These fibroblastswere cultivated on an HAMF12-DMEM medium (Sigma) supplemented by 10%(v/v) FCS (fetal calf serum). The GBA2 enzyme was over-expressed inHEK298T cells cultivated on a DMEM medium enriched with glucose (Gibco)supplemented by 10% NBS (newborn bovine serum) and 100 units/mL ofpenicillin/streptomycin (Gibco) and 5% CO₂ at 37° C. The activity of thecompounds on human β-glucosylceramide synthase (GCS) is evaluated insitu on cells of the RAW 264.7 type cultivated on an RPMI medium (Gibco)supplemented by 10% FCS, 1 mM of glutamax, 100 units/mL ofpenicillin/streptomycin (Gibco) and 5% CO₂ at 37° C.

The IC₅₀ values for the GANAB, GBA2 and GCS enzymes are determined fromcell lysates prepared in a buffer (20 mM hepes, 2 mM DTT, 0.25 Msucrose, 1 mM MgCl₂, 2.5 U/mL benzonase) at pH 7.0, and placed on icefor 30 minutes. These cell lysates are homogenized using a SilentCrushergrinder (Heidolph®), and then subjected to ultracentrifugation at 32,000rpm for 30 minutes at 4° C. The total protein concentration isdetermined in accordance with the Bradford method (Bradford, 1976, Anal.Biochem. 72: 248-254), using a Bradford BioRad Quick Start® kit (Pierce)and BSA (Sigma). The lysates are next aliquoted and stored at −80° C.before use.

The IC₅₀ values for the GANAB enzyme are determined on cell lysates offibroblasts of patients suffering from Pompe disease, using as a bufferthe Mcllvaine 150 mM, pH 7.0, 0.1% bovine serum albumin (BSA) (p/v), asubstrate (4-methyl-umbelliferone-α-D-glucopyranoside) concentration of2.4 mM and an incubation time of 2 hours.

The IC₅₀ values for the GBA1 enzyme are determined using as buffer theMcllvaine 150 mM, pH 5.2, 0.2% taurocholate (p/v), 0.1% Triton X-100(v/v), 0.1% bovine serum albumin (BSA) (p/v), an enzyme concentration of0.7 nM, a substrate (4-methyl-umbelliferone-β-Dglucopyranoside)concentration of 3.0 mM and an incubation time of 30 minutes.

The residual activity of GBA2 in the presence of the compounds isdetermined after pre-incubation for 30 minutes of the homogenates ofHEK298T cells over-expressing GBA2 with an inhibitor of GBA1, conduritolβ-epoxide (Sigma), at a concentration of 1 mM. The IC₅₀ values aredetermined on cell lysates, using as a buffer the Mcllvaine 150 mM, pH5.8, 0.1% bovine serum albumin (BSA) (p/v), a substrate(4-methyl-umbelliferone-β-D-glucopyranoside) concentration of 3.0 mM andan incubation time of 1 hour.

The residual activity of GCS in the presence of the compounds isdetermined after pre-incubation for 1 hour of the homogenates of RAW264.7 cells with an inhibitor of GBA1, conduritol β-epoxide (Sigma), ata concentration of 300 μM.

The I₅₀ values for the GCS enzyme are determined in situ in the cellculture medium at pH 7.0 using 1 μM of NBD-ceramide(N-[12-[(7-nitro-2-1,3-benzoxadiazol-4-yl)amino]dodecanoyl]-D-erythro-sphingosine)as substrate, as described in the aforementioned publication of Lahav etal.

The results obtained for all these tests are set out in tables 1 and 2below. In these tables, by way of comparison, the values obtained forthe compounds of the prior art DNJ and NB-DNJ, as described in theliterature, are also indicated. In these tables: ^(a) indicates Porto etal., 2012, Mol. Ther. 20: 2201-2211; ^(b) indicates Bruckmann et al.,2012, ChemMedChem 7: 1943-1953; ^(c) indicates Flanagan et al., 2009,Human Mut. 30: 1683-1692; ^(d) indicates D'Alonzo et al., 2017, J. Med.Chem. 60: 9462-9469; * indicates ΔTm measured at [compound]=10 times thevalue of K_(i); ^(e) indicates Asano et al., 1995, J. Med. Chem. 38:2349-56; ^(f) indicates Wennekes et al., 2010, J. Med. Chem. 53:689-698.

TABLE 1 rhGAA rhGAA rhGAA rhGAA (Fluopol- (residual ΔTm ΔTm Com- ABPP)activity) at pH at pH pound IC₅₀ (μM) IC₅₀ (μM) 4.0 (° C.) 7.4 (° C.)(IIa) 0.42 341 8.1 12.7 (IIb) 0.39 104 7.8 11.5 (Ki = 13 μM) (IIc) 0.2237.2 11.8 13.0 (K_(i) = 7.6 μM) (IId) 0.15 182 9.4 10.7 (K_(i) = 18.9μM) (IIf) 0.87 297 6.4 11.8 (IIg) 0.46 387 6.7 14.4 (IIh) 9.7 — — —(IIj) 15.2 — — — (IIk) 11.6 — — — (IIm) 45.0 — — — (IIn) 24.6 — — —(IIx1) — 40.3 — 16.5 (IIb7) — 31.6 — 16.8 (IIb3) — 29.6 — 16.9 (K_(i) =10.8 μM) (IIc1) — 32.9 — 15.0 (K_(i) = 13.0 μM) (IIr) — 29.5 — 14.5(K_(i) = 20.0 μM) (IIb1) — 49.1 —  6.2 (K_(i) = 6.4 μM) DNJ 0.41 K_(i) =3.4 μM^(a) 2.7 (pH 4.3)*^(b) 15^(c)   NB-DNJ — K_(i) = 3.1 μM^(b) 6.2(pH 4.3)*^(b) 12^(d)  

TABLE 2 GANAB GBA1 GBA2 GCS Compound IC₅₀ (μM) IC₅₀ (μM) IC₅₀ (μM) IC₅₀(μM) (IIa) >100 >1000 >1000 >50 (IIb) >100 >1000 >1000 >50(IIc) >100 >1000 >1000 >50 (IId) >100 >1000 >1000 >50(IIf) >100 >1000 >1000 >50 (IIg) >100 >1000 >1000 >50 DNJ     4.6^(e)  250^(f) 21 >100^(f)  NB-DNJ   15^(e)   400^(f) 0.23^(f)  50^(f)

All these results demonstrate a selectivity of the compounds used inaccordance with the invention for human acid α-glucosidase, comparedwith the other human enzymes tested. This selectivity is much greaterthan that of the molecules proposed by the prior art DNJ and NB-DNJ. Thecompounds used in accordance with the invention furthermore have animportant effect of stabilization of rhGAA, comparable to that of DNJand NB-DNJ.

Furthermore, the compounds (IIb7), (IIb3), (IIc1), (IIr) and (Ic),complying with the general formula (I″a), as well as the compound(IIx1), have performances superior to those of the other compoundsaccording to the invention.

1. A method of treating a subject, comprising administering to saidsubject a therapeutically-effective amount of a compound of generalformula (I), or one of the pharmaceutically acceptable salts thereof:

wherein R¹ represents a hydrogen atom or a linear, branched and/orcyclic hydrocarbon radical, saturated or unsaturated, aromatic or not,optionally substituted, optionally comprising one or more heteroatomsand/or one or more groups including at least one heteroatom andoptionally comprising a single ring or a plurality of rings optionallyfused, and R² represents a linear, branched and/or cyclic hydrocarbonradical, saturated or unsaturated, aromatic or not, optionallysubstituted, optionally comprising one or more heteroatoms and/or one ormore groups including at least one heteroatom and optionally comprisinga single ring or a plurality of rings optionally fused, said hydrocarbonradical comprising at least 2 carbon atoms when R¹ represents a hydrogenatom, or R¹ and R² form together, with the atoms of the piperidine ringto which each is attached, a 3-to 6-membered heterocycle fused with thepiperidine ring, optionally substituted by one or several radicals,which may be identical or different, each selected from the groupconsisting of a hydroxyl group, an amino group or a linear, branchedand/or cyclic carbon radical, saturated or unsaturated, aromatic or not,optionally substituted, optionally comprising one or more heteroatomsand/or one or more groups including at least one heteroatom andoptionally comprising a single ring or a plurality of rings optionallyfused.
 2. The method of claim 1, wherein, in the general formula (I): R¹represents a hydrogen atom or a linear, branched and/or cyclichydrocarbon radical, saturated or unsaturated, aromatic or not,optionally substituted, optionally comprising one or more heteroatomsand/or one or more groups including at least one heteroatom andoptionally comprising a single ring or a plurality of rings optionallyfused, and R² represents a —CH(R³)—R⁴ group, wherein R³ and R⁴,identical or different, each represent a hydrogen atom or a linear,branched and/or cyclic hydrocarbon radical, saturated or unsaturated,aromatic or not, optionally substituted, optionally comprising one ormore heteroatoms and/or one or more groups including at least oneheteroatom and optionally comprising a single ring or a plurality ofrings optionally fused, R³ and R⁴ not simultaneously representing ahydrogen atom when R¹ represents a hydrogen atom.
 3. The method of claim1, wherein, in the general formula (I): R¹ represents a hydrogen atom ora linear, branched and/or cyclic hydrocarbon radical, saturated orunsaturated, aromatic or not, optionally substituted, optionallycomprising one or more heteroatoms and/or one or more groups includingat least one heteroatom and optionally comprising a single ring or aplurality of rings optionally fused, and R² represents a —(CHR⁷)—SO₂—Ar¹group wherein Ar¹ represents an aryl or heteroaryl radical, optionallysubstituted, and R⁷ represents a hydrogen atom or a linear, branchedand/or cyclic hydrocarbon radical, saturated or unsaturated, aromatic ornot, optionally substituted, optionally comprising one or moreheteroatoms and/or one or more groups including at least one heteroatomand optionally comprising a single ring or a plurality of ringsoptionally fused.
 4. The method of claim 1, wherein, in the generalformula (I): R¹ represents a hydrogen atom or a linear, branched and/orcyclic hydrocarbon radical, saturated or unsaturated, aromatic or not,optionally substituted, optionally comprising one or more heteroatomsand/or one or more groups including at least one heteroatom andoptionally comprising a single ring or a plurality of rings optionallyfused, and R² represents a triazole group, optionally substituted. 5.The method of claim 1, wherein, in the formula (I): R¹ represents ahydrogen atom or a linear, branched and/or cyclic hydrocarbon radical,saturated or unsaturated, aromatic or not, optionally substituted,optionally comprising one or more heteroatoms and/or one or more groupsincluding at least one heteroatom and optionally comprising a singlering or a plurality of rings optionally fused, and R² represents a—(CH₂)₂—R⁸ group, wherein R⁸ represents: a hydrogen atom; a C1-C12 alkylor cycloalkyl group, optionally substituted, optionally comprising asingle ring or a plurality of fused rings; a —(CH₂)_(a)—OH group whereina is an integer between 0 and 18; a —(CH₂)_(b)—Ar² group wherein Arerepresents an aryl or heteroaryl radical, optionally substituted,optionally comprising one or more heteroatoms and/or one or more groupsincluding at least one heteroatom and optionally comprising a singlering or a plurality of rings optionally fused and b is an integerbetween 0 and 18; a —(CH₂)_(c)—Si(R⁹)₃ group wherein R⁹ represents ahydroxyl radical, a C1-C4 alkyl radical, a C1-C4 alkoxyl radical or aphenyl radical and c is an integer between 0 and 18; or a —(CH₂)_(d) 13Z—R¹⁰ group wherein Z is a heteroatom selected from the group consistingof oxygen, nitrogen and sulfur, R¹⁰ represents a hydrogen atom or aC1-C18 alkyl, cycloalkyl, alkylaryl, aryl or acyl radical, said radicaloptionally being interrupted and/or substituted by one or moreheteroatoms and/or one or more groups including at least one heteroatom,and d is an integer between 0 and
 18. 6. The method of claim 1, wherein,in the general formula (I), R¹ represents a C1-C18, linear, branchedand/or cyclic alkyl group, optionally interrupted and/or substituted byone or more heteroatoms and one or more groups including at least oneheteroatom.
 7. The method of claim 1, wherein said compound has thegeneral formula (I′a):

wherein: R¹ represents a hydrogen atom or C1-C18 linear, branched and/orcyclic alkyl group, optionally interrupted and/or substituted by one ormore heteroatoms and/or one or more groups including at least oneheteroatom, R⁸ represents: a hydrogen atom; a methyl, ethyl, propyl,butyl, pentyl, hexyl, cycloalkyl, adamantyl, alkylcycloalkyl, alkylarylor aryl radical, said radical optionally being interrupted and/orsubstituted by one or more heteroatoms and/or one or more groupsincluding at least one heteroatom; a hydroxyl group; a —Si(R¹²)₃ groupwherein R¹² represents a hydroxyl radical, a C1-C4 alkyl radical, aC1-C4 alkoxyl radical or a phenyl radical; a —(CH₂)_(f)—Y—R¹³ groupwherein f is an integer between 0 and 6, Y is a heteroatom selected fromthe group consisting of oxygen, nitrogen and sulfur and R¹³ represents aC1-C18 alkyl radical or a C1-C18 aryl or heteroaryl radical; a—(CH₂)_(g)—CO—R¹³ group wherein g is an integer between 0 and 6; or a—(CH₂)_(h)—SO_(e)—R¹³ group wherein h is an integer between 0 and 6 ande is equal to 1 or 2, R⁸ not representing a hydrogen atom when R¹represents a propyl radical.
 8. The method of claim 1, of wherein saidcompound has the general formula (I″a):

wherein: R¹ represents a hydrogen atom or a C1-C18 linear, branchedand/or cyclic alkyl group, optionally interrupted and/or substituted byone or more heteroatoms and/or one or more groups including at least oneheteroatom, R¹⁸ represents a linear, branched and/or cyclic hydrocarbonradical, saturated or unsaturated, aromatic or not, optionallysubstituted, comprising 4 to 18 carbon atoms, optionally comprising oneor more heteroatoms and/or one or more groups including at least oneheteroatom and optionally comprising a single ring or a plurality ofrings optionally fused.
 9. The method of claim 1, wherein said compoundhas the general formula (I′b):

wherein R¹⁴ represents a hydrogen atom, a carbonyl radical or a C1-C18alkyl, alkenyl, alkynyl, alkylaryl or aryl radical, said radicaloptionally being interrupted and/or substituted by one or moreheteroatoms and/or one or more groups including at least one heteroatom,and R¹⁵ represents a hydrogen atom, a hydroxyl radical, an aminoradical, or a C1-C18 alkyl, alkenyl or aryl radical, optionallyinterrupted and/or substituted by one or more heteroatoms and/or one ormore groups including at least one heteroatom.
 10. The method of claim1, wherein, in the general formula (I), R¹ and R² form together, withthe atoms of the piperidine ring to which each is attached, a 3-memberedheterocycle fused with the piperidine ring, optionally substituted by a—X—R⁵ group, wherein: X represents a —C(═O)— or —CH(OR⁶)— radicalwherein R⁶ represents a linear, branched and/or cyclic hydrocarbonradical, saturated or unsaturated, aromatic or not, optionallysubstituted, optionally comprising one or more heteroatoms and/or one ormore groups including at least one heteroatom and optionally comprisinga single ring or a plurality of rings optionally fused, and R⁵represents a hydrogen atom, an amino group, or a linear, branched and/orcyclic hydrocarbon radical, saturated or unsaturated, aromatic or not,optionally substituted, optionally comprising one or more heteroatomsand/or one or more groups including at least one heteroatom andoptionally comprising a single ring or a plurality of rings optionallyfused, or X represents a —CH(OH)— radical and R⁵ represents a hydrogenatom or a linear, branched and/or cyclic hydrocarbon radical, saturatedor unsaturated, aromatic or not, optionally substituted, optionallycomprising one or more heteroatoms and/or one or more groups includingat least one heteroatom and optionally comprising a single ring or aplurality of rings optionally fused.
 11. The method of claim 1, which isfor treating Pompe disease in said subject.
 12. The method as claimed inclaim 11, which is for stabilizing human acid α-glucosidase in saidsubject.
 13. (canceled)
 14. A pharmaceutical composition containing acompound of general formula (I) or one of the pharmaceuticallyacceptable salts thereof in a pharmaceutically acceptable vehicle;

wherein R¹ represents a hydrogen atom or a linear, branched and/orcyclic hydrocarbon radical, saturated or unsaturated, aromatic or not,optionally substituted, optionally comprising one or more heteroatomsand/or one or more groups including at least one heteroatom andoptionally comprising a single ring or a plurality of rings optionallyfused, and R² represents a linear, branched and/or cyclic hydrocarbonradical, saturated or unsaturated, aromatic or not, optionallysubstituted, optionally comprising one or more heteroatoms and/or one ormore groups including at least one heteroatom and optionally comprisinga single ring or a plurality of rings optionally fused, said hydrocarbonradical comprising at least 2 carbon atoms when R¹ represents a hydrogenatom, or R¹ and R² form together, with the atoms of the piperidine ringto which each is attached, a 3-to 6-membered heterocycle fused with thepiperidine ring, optionally substituted by one or several radicals,which may be identical or different, each selected from the groupconsisting of a hydroxyl group, an amino group or a linear, branchedand/or cyclic carbon radical, saturated or unsaturated, aromatic or not,optionally substituted, optionally comprising one or more heteroatomsand/or one or more groups including at least one heteroatom andoptionally comprising a single ring or a plurality of rings optionallyfused.
 15. The pharmaceutical composition of claim 14, which is in aform suitable for oral administration.
 16. A compound of general formula(I′):

wherein R¹ represents a hydrogen atom or a linear, branched and/orcyclic hydrocarbon radical, saturated or unsaturated, aromatic or not,optionally substituted, optionally comprising one or more heteroatomsand/or one or more groups including at least one heteroatom andoptionally comprising a single ring or a plurality of rings optionallyfused, and R² represents a —CH(R³)—R⁴ group, wherein R³ and R^(4,)identical or different, each represent a hydrogen atom or a linear,branched and/or cyclic hydrocarbon radical, saturated or unsaturated,aromatic or not, optionally substituted, optionally comprising one ormore heteroatoms and/or one or more groups including at least oneheteroatom and optionally comprising a single ring or a plurality ofrings optionally fused, R³ and R⁴ being such that, when R¹ and R³ eachrepresent a hydrogen atom, R⁴ does not represent a hydrogen atom or aphenyl radical, and R¹ and R² being such that they do not simultaneouslyrepresent, respectively, a propyl radical and an ethyl radical, or R¹and R² form together, with the atoms of the piperidine ring to whicheach is attached, a 4-membered heterocycle fused with the piperidinering, optionally substituted by one or more radicals, which may beidentical or different, each selected from the group consisting of ahydroxyl group, an amino group or a linear, branched and/or cycliccarbon radical, saturated or unsaturated, aromatic or not, optionallysubstituted, optionally comprising one or more heteroatoms and/or one ormore groups including at least one heteroatom and optionally comprisinga single ring or a plurality of rings optionally fused, or R¹ and R²form together, with the atoms of the piperidine ring to which each isattached, a 3-membered heterocycle fused with the piperidine ring,optionally substituted by a —X—R⁵ group, wherein: X represents a —C(═O)—or —CH(OR⁶)— radical wherein R⁶ represents a linear, branched and/orcyclic hydrocarbon radical, saturated or unsaturated, aromatic or not,optionally substituted, optionally comprising one or more heteroatomsand/or one or more groups including at least one heteroatom andoptionally comprising a single ring or a plurality of rings optionallyfused, and R⁵ represents a hydrogen atom, an amino group or a linear,branched and/or cyclic hydrocarbon radical, saturated or unsaturated,aromatic or not, optionally substituted, optionally comprising one ormore heteroatoms and/or one or more groups including at least oneheteroatom and optionally comprising a single ring or a plurality ofrings optionally fused; or X represents a —CH(OH)— radical and R⁵represents a hydrogen atom or a linear, branched and/or cyclichydrocarbon radical, saturated or unsaturated, aromatic or not,optionally substituted, optionally comprising one or more heteroatomsand/or one or more groups including at least one heteroatom andoptionally comprising a single ring or a plurality of rings optionallyfused, R⁵ not representing an n-propyl radical, a cyclohexyl radical ora phenyl radical, or one of the pharmaceutically acceptable saltsthereof.
 17. The compound of claim 16, wherein, in the formula (I′): R¹represents a hydrogen atom or a linear, branched and/or cyclichydrocarbon radical, saturated or unsaturated, aromatic or not,optionally substituted, optionally comprising one or more heteroatomsand/or one or more groups including at least one heteroatom andoptionally comprising a single ring or a plurality of rings optionallyfused, and R² represents a —(CHR⁷)—SO₂—Ar¹ group wherein Ar¹ representsan aryl or heteroaryl radical, optionally substituted, and R⁷ representsa hydrogen atom or a linear, branched and/or cyclic hydrocarbon radical,saturated or unsaturated, aromatic or not, optionally substituted,optionally comprising one or more heteroatoms and/or one or more groupsincluding at least one heteroatom and optionally comprising a singlering or a plurality of rings optionally fused.
 18. 1 The compound ofclaim 16, wherein, in the formula (I′): R¹ represents a hydrogen atom ora linear, branched and/or cyclic hydrocarbon radical, saturated orunsaturated, aromatic or not, optionally substituted, optionallycomprising one or more heteroatoms and/or one or more groups includingat least one heteroatom and optionally comprising a single ring or aplurality of rings optionally fused, and R² represents a triazole group,optionally substituted.
 19. The compound of claim 16, wherein, in theformula (I′): R¹ represents a hydrogen atom or a linear, branched and/orcyclic hydrocarbon radical, saturated or unsaturated, aromatic or not,optionally substituted, optionally comprising one or more heteroatomsand/or one or more groups including at least one heteroatom andoptionally comprising a single ring or a plurality of rings optionallyfused, and R² represents a —(CH²)₂—R⁸ group, wherein R⁸ represents: ahydrogen atom; a C1-C12 alkyl or cycloalkyl group, optionallysubstituted, optionally comprising a single ring or a plurality of fusedrings; a —(CH₂)_(a)—OH group wherein a is an integer between 0 and 18; a—(CH₂)_(b)—Ar² group wherein Are represents an aryl or heteroarylradical, optionally substituted, optionally comprising one or moreheteroatoms and/or one or more groups including at least one heteroatomand optionally comprising a single ring or a plurality of ringsoptionally fused and b is an integer between 0 and 18; a—(CH₂)_(c)—Si(R⁹)₃ group wherein R⁹ represents a hydroxyl radical, aC1-C4 alkyl radical, a C1-C4 alkoxyl radical or a phenyl radical and cis an integer between 0 and 18, or a —(CH₂)_(d)—Z—R¹° group wherein Z isa heteroatom selected from the group consisting of oxygen, nitrogen andsulfur, R¹⁰ represents a C1-C18 alkyl, cycloalkyl, alkylaryl, aryl oracyl radical, said radical optionally being interrupted and/orsubstituted by one or more heteroatoms and/or one or more groupsincluding at least one heteroatom, and d is an integer between 0 and 18.20. The compound of claim 16, of general formula (I′a):

wherein R¹ represents a hydrogen atom or a C1-C18 linear, branchedand/or cyclic alkyl group, optionally interrupted and/or substituted byone or more heteroatoms and/or one or more groups including at least oneheteroatom, R⁸ represents: a hydrogen atom; a hydroxyl group; a methyl,ethyl, propyl, butyl, pentyl, hexyl, cyclohexyl, adamantyl,alkylcycloalkyl, alkylaryl or aryl radical, said radical optionallybeing interrupted and/or substituted by one or more heteroatoms and/orone or more groups including at least one heteroatom; a —Si(R¹²)₃ groupwherein R¹² represents a hydroxyl radical, a C1-C4 alkyl radical, aC1-C4 alkoxyl radical or a phenyl radical; a —(CH₂)_(f)—Y—R¹³ groupwherein f is an integer between 0 and 6, Y is a heteroatom selected fromthe group consisting of oxygen, nitrogen and sulfur and R¹³ represents aC1-C18 alkyl radical or a C1-C18 aryl or heteroaryl radical; a—(CH₂)_(g)—CO—R¹³ group wherein g is an integer between 0 and 6; or a—(CH₂)_(h)—SO_(e)—R¹³ group wherein h is an integer between 0 and 6 ande is equal to 1 or 2, R⁸ not representing a hydrogen atom when R¹represents a propyl radical.
 21. The compound of claim 16, of generalformula (I″a):

wherein: R¹ represents a hydrogen atom or a C1-C18 linear, branchedand/or cyclic alkyl group, optionally interrupted and/or substituted byone or more heteroatoms and/or one or more groups including at least oneheteroatom, R¹⁸ represents a linear, branched and/or cyclic hydrocarbonradical, saturated or unsaturated, aromatic or not, optionallysubstituted, comprising from 4 to 18 carbon atoms, optionally comprisingone or more heteroatoms and/or one or more groups including at least oneheteroatom and optionally comprising a single ring or a plurality ofrings optionally fused.
 22. The compound of claim 16, of formula (I′b):

wherein R¹⁴ represents a hydrogen atom, a carbonyl radical or a C1-C18alkyl, alkenyl, alkynyl, alkylaryl or aryl radical, said radicaloptionally being interrupted and/or substituted by one or moreheteroatoms and/or one or more groups including at least one heteroatom,and R¹⁵ represents a hydrogen atom, a hydroxyl radical, an amino radicalor a C1-C18 alkyl, alkenyl or aryl radical, optionally interruptedand/or substituted by one or more heteroatoms and/or one or more groupsincluding at least one heteroatom.
 23. The compound of claim 16, offormula (I′c):

wherein R¹⁶ represents a hydrogen atom or a C1-C18 alkyl radical, saidradical optionally being interrupted and/or substituted by one or moreheteroatoms and/or one or more groups including at least one heteroatom,R¹⁶ not representing an n-propyl radical, a cyclohexyl radical or aphenyl radical.
 24. A method for preparing the compound of claim 19,comprising successive steps of: a/ reacting a compound of generalformula (III) or (IV) of formulae:

wherein Bn represents a benzyl radical, with a compound of generalformula (V):

wherein R⁸ is as defined in claim 19, R⁸ however representing neither ahydrogen atom, nor a hydroxyl group, nor an amino group, in the presenceof an organometallic compound, b/ optionally, reduction of thehydroxylamine function into amine, c/ optionally, alkylation of thenitrogen atom of the piperidine ring, d/ and hydrogenolysis of theproduct obtained at the end of step a/, where applicable of step b/ orof step c/.